Bulletin BULLETIN of the \ ILLINOIS NATURAL HISTORY SURVEY i HARLOW B. MILLS, Chief \ Hill Prairies of Illinois ROBERT A. EVERS Printed by Authority of the STATE OF ILLINOIS WILLIAM G. STRATTON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION VERA M. BINKS, Director «/srof?y suRm UBRARY STATE OF ILLINOIS William C}. Strattov, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Vera M. Binks, Director NATURAL HISTORY SURVEY DIVISION Harlow B. Mills, Chief \^olume 26 BULLETIN Article 5 Hill Prairies of Illinois ROBERT A. EVERS Printed by Authority of the State of Illinois URBANA, ILLINOIS August 1955 STATE OF ILLINOIS William G. SrRATros. Governor in-:i'ARTMENT OF REGISTRATION AND EDUCATION Veka M. BiNKS, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Vera M. Binks, Chairman A. E. Emerson. Ph.D., Biology L. H. Tiffany. Ph.D., Forestry Walter H. Newhouse, Ph.D.. Ceologv Roger Adams. Ph.D., D.Sc. Chemistry RoHERT H. .\ndekson. B.S.C.E., EnRineerinii Lloyd Morey, B.A., B.Mus., C.P.A., LL.D.. D.Sc. President of the University of Illinois Delyte W. Morris, Ph.D., President of Southern Illinois University NATURAL HISTORY SURVEY DIVISION Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF HARLOW B. MILLS. Ph.D., Chief Bessie B. East, M.S., Assislanl to the Chief Section of Economic Entomolotiy George C. Decker. Ph.D., Entomologist and Head J. M. Bigger, M.S., Entomologist L. L. English, Ph.D., Entomologist S. C. Chandler. B.S., Associate Entomologist Willis N. Brick, Ph.D., Associate Entomologist Norman C. Gan.non, Ph.D., Associate Ento- mologist John M. Wright, Ph.D.. Associate Entomologist Pall Si-ranyi, Ph.D.. Associate Entomologist W. H. LrcKMANN, M.S., Associate Entomologist Ronald H. Meyer. B.S., Assistant Entomologist John W. Matfeson, B.-v., Field Assistant Robert Snetsinger, M.S., Field Assistant Sl'E E. Watkins, Technical Assistant H. B. Petty, Ph.D., Extension S[>ecialist in En- tomology* Stevenson Moore, III, Ph.D., Extension Spe- cialist in Entomology* John Arthur Lowe, B.S., Research Assistant* Mohan Rao, M.S., Research Assistant* Clarence E. White, B.S.. Research Assistant* LorisE Zingrone, B.S., Research Assistant* Section of Faunistic Surveys and Insect Identification H. H. Ross, Ph.D., Systematic Entomologist and Head Milton W. Sanderson, Ph.D., Taxonomist Lewis J. Stannard, Jr., Ph.D., Associate Tax- onomist Philip W. Smith, Ph.D., Associate Taxonomist Leonora K. (jLOVD, M.S., Assistant Taxonomist Tho.mas E. Moore, M.S., Technical Assistant Barhaha GrTow->KV, M.A., Technical Assistant Section of Aquatic Biology George W. Bennett, Ph.D., Aquatic Biologist and Head William C. Starrett, Ph.D., Aquatic Biologist R. W. Larimore, Ph.D., Associate Aquatic Bi- ologist Donald F. Hansen, Ph.D., Assistant Aquatic Biologist Robert D. Crompton, Field Assistant Leonard Durham, M.S., Research Assistant* William F. Childers, B.S., Technical Assistant * Section of Applied Botany and Plant Patholofiy J. Cedric Carter, Ph.D., Plant Pathologist and Head J. L. Fo:<^berg. Ph.D., Plant Pathologist G. H. BoEWE, M.S., Associate Botanist R. J. Campana, Ph.D., Assistant Plant Pathol- ogist I. R. Schneides, Ph.D., Assistant Plant Pa- thologist E. B. Hi.MELiCK, M.S., Assistant Plant Patholo- gist Robert A. Evers, Ph.D., Assistant Botanist Rovenia F. Fifz-Gerald, B.A., Technical Assistant James D. Bildruck, M.S., Research Assistant* Section of Game Research and Management T. G. Scott, Ph.D., Game Specialist and Head Ralph E. Yeatter. Ph.D., Game Specialist F. C. Bellrose, B.S., Game Specialist H. C. Hanson, M.S., Assistant Game Specialist J. S. Jordan, Ph.D., Assistant Game Technician Ross J. Miller, M.S., Field Ecologisl Frances D. Rohbins, B.A., Technical Assistant Virginia A. Whipple, Technical Assistant John M. Schilling, Field Assistant William B. Robertson, Jr., Ph.D., Research Assistant* Ja.mes Opsahl, .M.S.. Field Assistant* Section of Publications and Public Relations Jamet S. Avars, B.S., Technical Editor and Head Blanche P. Young, B.A., Assistant Technical Editor William E. Clark, Assistant Technical Pholog- raper Milan Dourovic, B.A., Technical Assistant Technical Library Ruth R. Warrick, B.S., B.S.L.S., Technical Librarian Olga E. Griminger, M.S., Assistant Technical Libraria i Consultants: Herpetologv, Hobart M. Smith, Ph.D., Associate Professor of Zoology, University of Ulinois; Parasitology, Norman D. Levine, Ph.D., Professor of Veterinary Parasitology and of Veterinary Re- search, University of Illinois. Employed on co-operative projects with one of several agencies: Illinois Agricultural Extension Service, Illinois Department of Conservation, United States Army Surgeon General's Office, United States Depart- ment of Agriculture, United States Fish and Wildlife Service, United States Pulilic Health Service, and others. Thin ftain-r in a contrihttliitti front tho Sfctioii nf Aitplivd lintaiiy and Plant Pathology ( ] (,W,Z—LM— 5-5.J I ...fi.'V. • .^ 2 CONTENTS Acknowledgments 35g Environment 37O Climate 37O Temperature 37O Precipitation 372 Frost 372 Wind 372 Physiography and Geology 372 Surficial Material 372 Exposure 373 Altitude 375 Parallel Tributary Valleys 375 Environmental Conclusions 375 Vegetation of Hill Prairies 375 Phegley and Sampson Prairies 375 Study Procedures 378 Sizes and Shapes of Study Plots 379 Method of Counting Plant Units 380 Density of Vegetation 381 Grasses 381 Plants Other Than Grasses 382 Total Densities 383 Ground Space of Plants 383 Phegley Prairie 383 Sampson Prairie 384 Foliage Area or Crown Cover 384 Available Space per Plant 386 Numbers of Plant Species for Various Plot Sizes 387 Sampson Prairie 387 Phegley Prairie 387 Frequency of Occurrence of Species 389 Sampson Prairie 389 Phegley Prairie 390 Frequency Values for Combinations of Species 390 Species-Area Curve 391 Summary of Pastured and Unpastured Prairies 392 Vegetation Characters From Other Stands 392 Presence 392 Seasonal Aspect 393 Vegetational History and Succession 393 Annotated List of Hill Prairies 395 East Dubuque to Grafton 396 Along Rock, Sangamon, and Illinois Rivers 401 Grafton to Cairo and Elsewhere in Southern Illinois 405 Flora of the Hill Prairies 413 Annotated List of Species 414 Geographical Relations of the Hill Prairie Flora 441 Summary 441 Literature Cited 444 #^^^ Hill Prairies of Illinois ROBERT A. EVERS ON the sunny, windswept, upper slopes of some of the bluffs along the major Illinois streams are tree- less areas distinctive enough to attract the attention of observing travelers. These areas are grassy strips or grassy openings on the otherwise forested slopes of the bluffs, frontispiece. Most of them have been little disturbed by man or domesti- cated animals. Those that are covered with prairie plants are prairies. Prairies are grasslands. To many per- sons, prairies are flat grasslands. How- ever, it is not topography but vegetation that distinguishes prairies and other plant communities. Forests occur on flat land or on slopes. So do prairies. Grasslands, or prairies, on pronounced slopes are ///'// prairies. The term hill prairies was first used in 1943 by a University of Illinois botanist. Dr. Arthur G. Vestal, in his ecology classes and seminars to characterize prai- ries that occur on loess bluffs, on mounds, on steep, rocky slopes, on steep slopes of glacial drift, or on any other steep slopes. With few exceptions, the hill prairies of Illinois are not hill-top prairies; most of them occupy only the upper west- and southwest-facing slopes of elevations. Most of the once extensive flatland prairies have disappeared from the Illinois landscape. There yet remain a few patches of these prairies on the till plains, but they have been very much disturbed by man or domesticated animals. The prairies of the bottomlands, the type stud- ied by Turner (1934fl, 1934Z'), now occur only in small scattered patches, usually in field borders or borders of roadside ditches in the Mississippi and Illinois river val- leys. There are still sizable areas of sand prairies of the tvpe studied bv Gleason (1910). Gates (1912), Vestal (1913), •This article is based upon a thesis submitted by the writer to the Graduate College, University of Illinois, Urbana, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Botany. and others, but the extent of these prairies is rapidly decreasing as a result of the ac- tivities of man in converting them to fields of w^atermelons or cantaloupes, or to an- other type of grassland, the cornfield. There remain on the Illinois landscape numerous tracts of hill prairie and, as these prairie slopes were never plowed, they are now the least disturbed type of prairie in the state. Although rather com- plete studies of till plain, bottomland, and sand prairies of Illinois have been pub- lished, until this time no comparable study has been done for the hill prairies of this state. Several studies have been published on the hill prairies of other states. The study by Bush (1895) on the mound flora of Atchison County, Missouri, and the work of Steyermark (1940) on suc- cession in Ozark glades of the same state concerned, in part, prairie on pro- nounced slopes. Studies of Pammel (1896, 1899, 1902) and Shimek (1910a, 1910/', 1911, 1924) described the vegeta- tion and enumerated the species of the loess bluff prairies in western Iowa or of the prairie openings or grassy meadows on the Iowa bluffs of the Mississippi River. Reports of Hanson (1922), of Costello (1931), and of Hopkins (1951) described prairies on loess bluffs along the Missouri River in Nebraska or prairies on loess hills in central Nebraska. A paper by IVIarks (1942) characterized what he termed the "goat prairies" of Wisconsin as prairies located on slopes "so steep that only the nimble goat could graze them." Sites described in these papers were prai- ries on steep slopes, or hill prairies. Perhaps the earliest reference in the lit- erature to Illinois grasslands on the upper slopes of bluffs is found in reports on the geology of Greene County and of Scott County by Worthen (1868). In these re- ports, Worthen described loess-capped bluffs with grass-covered knobs. These [ 367 ] .?b8 li-i.iNOis N.MLRAi. History Slrvhv Bulletin Vol. 26, Art. 5 grassy knobs wt'ic prairies on steep slopes, or hill prairies. It is surprising that no earlier descriptions of hill prairies are ex- tant. Certainly the French settlers saw the grassy slopes and perhaps named the \illage of Prairie du Rocher (Prairie of the Rock) after the prairie above the clififs. 'I'he capable botanist, Andre Michaux, who traveled from Kaskaskia to Cahokia and visited the village of Prairie du Rocher in 17*^)5, apparentl\ made no rec- ord, in that part of his journal included by Sargent (1889), of grasslands on the bluffs. Earlv gazetteers, as those of Peck (1834) and Ellsworth (1837), contain references to wet, dry, level, and undulat- ing prairies, but apparently nothing about prairies on the bluff's. Short (1845) wrote a good description of the autumnal aspect of flatland prairies; his journey did not take him far enough to the west to include hill prairies. Some references to hill prairies of Illi- nois have appeared in the past 50 vears. Hus (1908) described the bluffs in the vicinity of Collinsville and mentioned open hillsides with grasses dominant and blue- grass the chief species. Vestal (1918) cited numerous prairie inclusions near Charleston, described their topography, and stated essential conditions for their presence. Woodard (1924) mentioned prairies on bluff-ridges. Vestal (1931) reported the occurrence of prairies on loess bluffs of the Mississippi River, and Vestal & Bartholomew (1941) briefly described some prairies on the loess bluffs of the Illinois River. These authors were concerned only with local occurrences of hill prairies in Illinois. They did not report on the ex- tent of hill prairies in the state, nor did they report in detail on the flora of the hill prairies, the characteristic plants, relative abundance, presence and space relations as determinable in plot studies, or the origin and history of hill prairies. In order to obtain the necessary infor- mation for a study of these characteristics of hill prairies and for a description of hill prairie vegetation in Illinois, the writer made numerous plant collections and plant identifications from 61 hill prai- ries, fig. 1, having a combined area of more than 200 acres. Detailed data pertaining to the vegetation were obtained from two prairies by use of plot studies, as explained in a later section of this paper. The locations of some hill prairies were determined by the writer from the field notes made by Dr. Vestal during his trav- els in the state ; of others, as the prairie southeast of Menominee Station in Jo Daviess County, from a study of aerial photographs. The majority, however, were found by field reconnaissance of the writer. During late autumn and early spring, hill prairies can easily be seen from the roads near or at the bases of the bluffs. Such roads, called bluff roads on some maps, are common in both the Mis- sissippi and Illinois river valleys. In the Mississippi River valley, bluff roads were traveled by the author from Olive Branch in Alexander County northward to a point north and west of Glen Carbon in Madison County and from Hamburg in Calhoun Count_\' the 275-mile distance to the northwest corner of the state, except for short gaps in Hancock, Henderson, Mercer, Rock Island, and Jo Daviess counties. In the lower Illinois River val- ley, bluff roads were traveled from Graf- ton to Hennepin, except for a few gaps in Mason and Tazewell counties. The lo- cations of prairie sites were marked on maps of sufficient scale to be used easily. Not all hill prairies seen were visited, nor were bluffs of small streams exam- ined for occurrences of hill prairies. Doubtless small prairie openings occur on the bluffs of small streams in the western part of the state. In eastern Illinois, Ves- tal (1918) observed several prairie open ings along the Embarrass River near Charleston. ACKNOWLEDGMENTS I It is indeed a pleasure to acknowledge the assistance given by Dr. A. G. Vestal, Department of Botany, University of Illi- nois, in the preparation of this study. I wish to thank him for his willingness to direct this investigation and for the many helpful suggestions he made during its progress. Dr. L. R. Tehon, now deceased, and Dr. H. B. Mills, of the Natural History Survey, greatly facilitated the progress of August, 1955 EvERS: Hill Prairies of Illinois 369 SEEN, BUT NOT VISITED NOR DESCRIBED Fig. 1.—Location of the Illinois hill prairies which the author visited and of those which he saw only from a distance during the field work for th^s report. Hill prairies are most numerous on bluffs that trend northwest and southeast and have upper slopes facing the southwest. Bluffs of tributary streams were not examined for occurrences of hill prairies. MO Illinois Natural History Survey Bulletin Vol. 26, Art. 5 this stuil\ ; for their help 1 am trulv grate- ful. Also, 1 wish to acknowledge here the assistance given hy Mr. \V. H. Phejiley antl Mr. J. J. Steibel of Prairie du Rocher. Ivith of whom are now deceased. Some of the ve^jetation studies for this in- vestigation were accomplished through their kind co-operation. I wish to thank Dr. G. \V. W'hite, Department of Geol- ogy. University of Illinois, and Dr. H. H.'Willman and Dr. G. E. Ekblaw, Illi- nois State (Geological Survey, for infor- mation concerning the geolog)' of hill prairies; Mr. B. M. Woods, University Library Map Room, for his efforts to lo- cate suitable aerial photographs; Mr. Julian Neill. East St. Louis, for assist- ance in the study of hill prairies in that region; Dr. J. L. Forsberg, Dr. P. F. Hoffman, Mr. J. W. Curfman, and Mr. R. E. Teegardin, while members of the Natural History Survey stafif, for assist- ance with the statistics, the hydrogen-ion determinations, and the maps, diagrams, and drawings; and Mr. J. S. Ayars, also a Survey staff member, for his assistance with editorial problems. Others I wish to thank for their con- tributions to this investigation are Dr. M. VV. Sanderson, Dr. H. H. Ross, Dr. L. J. Stannard, Illinois Natural History Survey; Mr. and Mrs. F. W. Evers, Quincy; Mr. Raymond Hatcher, Mur- ph\sboro; Dr. J. W. Hall, University of Minnesota; Mr. and Mrs. B. C. Trees, East St. Louis; Frederick Evers, Clara V. Evers, and Marilyn Briggs Ellerman, Champaign; and Miss V^irginia Frank, Chicago. Mr. Dewey Clark, Quincy, took the pictures for the frontispiece and fig. 16. Mr. W. E. Clark, Natural History Sur- vey stafif, took the photographs used as figs. 3, 17, 18, 22, and 24. All other photographs were taken by the author. The plant nomenclature used in this study is for the most part that of Hitch- cock (1950) for grasses and Fernald (1950) for other plants. Where the no- menclature in this report does not con- form to that in the manual of Hitchcock or that of Fernald, the manual name is included in brackets in the section on the flora of hill prairies. In instances in which a name of long standing has been changed in recent manuals, the former name, in brackets, also appears. Common names not from the above manuals are from Deam (1940) or Jones (1950). ENVIRONMENT The occurrence and distribution of plants, and consequently plant communi- ties, is determined largely by climate and other environmental conditions, including the soil or substratum in which they grow. Some of the environmental conditions fa- voring the existence of hill prairies in Illi- nois are discussed in the following sec- tions. The climate in practically any part of Illinois permits growth of either prairie or forest. The circumstances (aside from those of accident and of history) which tip the balance and thus determine the details of local distribution of prairie and forest are chiefly the controls exerted by topography. Climate The following information on climatic conditions applies to the Mississippi River valley along the western border of Illi- nois, the region of the majority of hill prairies observed for this report. With few exceptions, the climatic data, taken from Page (1949), are from weather sta- tions located along the Mississippi River. Exceptions are the data from the Mount Carroll, Carbondale, Anna, and Green- ville weather stations ; these stations are, respectively, about 9, 11, 12, and 33 miles from the nearest hill prairies. Temperature.—The average January temperature along the western border of Illinois varies from 19.6 degrees Fahren- heit in northwestern Illinois (Dubuque, Iowa, weather station) to 36.2 in south- ern Illinois at Cairo. The average July temperature is 74.6 degrees in northwest- ern, 80.2 in west-central (Quincy weather station), and 79.8 in southwestern and southern Illinois (St. Louis, Missouri, and Carbondale, Illinois, weather sta- tions). In Cairo, at the southernmost weather station in Illinois, the average July temperature is 79.5 degrees. The re- August, 1955 EvERs: Hill Prairies of Illinois 371 ^' ^•^'C^i ^-*.'.-iB>. <^5i*Bar^ V i* *-ir:5^;i>- '*>' Fig. 2.—An excavation in the toe or basal slope of a bluff southwest of Renault, Monroe County, which shows the characteristics of the rock fragments that form the basal slopes of many river bluffs. The fragments have spalled from the cliff above the slope. .?72 Illinois Natlral History Survey Bulletin Vol. 26, Art. 5 corded extremes of temperature are -35 degrees at Mount Carroll (January 22, 1Q30) and 115 degrees at Greenville (July, 1036). The highest recorded tem- perature in that part of Illinois along the Mississippi River is 114 degrees, recorded at Quincy in July, 1*^36. Precipitation.—The average annual precipitati»)n along the western horder of Illinois varies from 33.13 inches in northwestern Illinois ( Duhuque, Iowa, weather station) to 41.39 at Cairo and 47.43 at Anna. Averages of snowfall, notahly less than 10 per cent of the an- nual precipitation, are 9.9 inches at Cairo and M3 at Mount Carroll. The wettest month in northern and west-central Illi- nois is June. The wettest month in south- ern Illinois varies with location; May is the wettest month at Anna, March the wettest at Cairo. During the growing season, April through September, Cairo receives 49.41 per cent of its annual rain- fall ; Anna, 52.77 per cent ; Quincy, 65.26 per cent; and northwestern Illinois (Du- buque, Iowa, weather station), 66.77 per cent. Frost.—The average frost-free periods along the western border of Illinois are April 19 to October 16 in northwestern Illinois (Dubuque, Iowa, weather sta- tion), April 13 to October 20 at Quincy in west-central Illinois, April 9 to Octo- ber 26 at Anna, and March 30 to Octo- ber 29 at Cairo. Wind.—The prevailing wind in winter a'ong the western border of Illinois is from the northwest ; in summer, it is from the southwest, often hot and dry. Physiography and Geology Steep slopes or bluffs abut the broad, deeply alluviated floodplains or bottom- lands of many of the major stream valleys in Illinois. The continuity of the bluffs is broken by tributary streams that enter the main valleys. The underlying bed- rock and the surficia! material determine the form of the bluffs. The bedrock of the bluffs on which hill prairies occur is limestone, dolomite, sand- stone, shale, or combinations of these ; the geological ages of the uppermost strata range from Middle Ordovician to Upper Pennsylvanian. In most places, the bed- rock crops out to form a cliff as much as 200 feet above the valley floor. Fre- quently, a stony talus or to? slope is pres- ent at the base of the cliff, fig. 2, and, un- less recently disturbed, supports a mixed forest. A mantle of surficial material cov- ers the bedrock at the top and forms the brow or upper slope of the bluff. In some places, as in parts of Morgan and Madi- son counties, sandy loess and colluvium completely mantle and conceal the bed- rock. Surficial Material.—Surficial mate- rial, the unconsolidated material above the bedrock, may be residual or trans- ported. Residual material, which sup- ports both prairie and forest in Illinois, occurs south of the glaciated area, as, for instance, on the rocky slopes at Cave Creek prairie and the cherty ridge-top at Tamms. On most other prairie slopes the surficial material is transported—loess or glacial drift. Loess, a windblown accumulation of silt with subordinate clay and minor amounts of fine sand, occurs over large areas of the Midwest. "One of the most important and best-known occurrences of loess in the world is in the Mississippi River Basin" (Leighton & Willman 1950). Loess mantles most of Illinois ex- cept the large stream valleys and areas of lake sediments and sand dunes. The eolian hypothesis of the origin of loess deposits is the one accepted by most geologists who have studied this material extensively. Udden (1894) wrote. "From a dynamical point of view the wind-the- ory would appear to furnish an adequate explanation of the occurrence of the loess in the Mississippi valley, at least as to most of its phases." Shimek (1896) ad- vocated the eolian hypothesis and based his conclusions in part upon the land snail shells he found in loess. Chamberlin (1897) presented the hypothesis that loess (of the Mississippi V^alley) is a wind de- posit and that the sources of the material were the floodplain deposits of the glacial rivers. The hypothesis of the origin of loess deposits from backswamp sediments (Russell 1944) does not seem tenable for Illinois. The thickest loess deposits in Illinois August, 1955 EvERS: Hii.L Prairies of Illinois 373 are found along the east bluffs of the Mississippi and Illinois rivers, where, in some places, they are more than 300 inches in depth. Such thick deposits occur in places where the valley changes from a northwest-southeast trend to one that is north-south or northeast-southwest, as in In Illinois, soils derived from loess sup- port both prairie and forest. The only bluff prairie slopes that are mantled by glacial drift and that the writer examined for this report are in Putnam County. These bluff's were last covered bv ice during the Tazewell sub- n 574 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 higiier temperatures. Such slopes, espe- cially those of high hlufts, are also directly exposed to the prevailing southwesterly STAGE August, 1955 EvERs: Hill Prairies of Illinois 375 Hill prairies are absent from the gener- ally northeast-facing slopes of the bluffs on the southwest sides of valleys ; these slopes are covered by forests except where they have been cleared and are now in cul- tivation. Altitude.—A relationship apparently exists between height of the bluffs and oc- currence of hill prairies. More prairie openings and prairie strips are found on the Mississippi River bluffs in Pike, Cal- houn, Monroe, and Randolph counties where the bluffs are high than on those bluffs just north or south of Quincy in Adams County where the bluffs are low. At Clendenny prairie (Calhoun County), the bluff rises 220 feet above the bottom- land ; at Sessions ( Pike County) , 240 feet ; at Fults (Monroe County), 340 feet; and at Phegley and Sampson (Randolph County), 310 feet. The bluffs north of Quincy are only slightly more than 100 feet and those south of Quincy are but 120 feet above the Mississippi River bot- tomland. Parallel Tributary Valleys.—Dur- ing the course of field work, the writer observed an interesting feature of the bluffs. In 34 of the 61 hill prairies vis- ited, tributary valleys are found approxi- mately parallel to and short distances back of the bluffs, fig. 5. In each of the 34 sites, the area between the major stream valley and the parallel valley, or valleys, is a narrow ridge that is joined to the up- land beyond by another narrow ridge more or less at right angles to the bluff. Hill prairies grow on the upper slope of the ridge that faces the major stream valley, a slope referred to as the upper bluff slope or the brow slope. Narrow ridges of this type occur where streams have cut back into the valley wall and where, at ap- proximately right angles to them, their tributaries have developed. The tributary valleys, mostly parallel to the bluffs, are V-shaped and forest covered. Environmental Conclusions As the climate and soils of Illinois per- mit the growth of both prairie and forest, it can be concluded that certain geomor- phic conditions are accountable for the oc- currence of hill prairies on the upper bluff slopes. Location, the p'ace in reference to major stream valleys, and topography, largely the result of the geomorphic his- tory of the region, exert strong influences, or controls, that are responsible for the presence of hill prairies. The growth of grassland rather than forest on the upper bluff slopes is attributed to priority of oc- cupation by prairie species and to the xeric conditions that are produced by the combination of local exposure to the sun and to the wind (especially to wind mov- ing unimpeded across wide floodplains), the height of the bluffs above the adjacent bottomlands, the steepness and direction of the upper slopes, and the permeability of the substratum. Thus, the hill prairie community is the result of a complex set of conditions, the effectiveness of which is determined by location and topography. VEGETATION OF HILL PRAIRIES The typical vegetation of hill prairies is the bunch-grass type. In most places, Andropoffon scoparius is the dominant spe- cies. In some places, such bunch grasses as Bouteloua curtipeudula, A. gerardi, and Sorghastrum nutans are locally dom- inant. In order to learn about the vege- tation, its density, the ground space it oc- cupies, the foliage area or crown cover, the available space per plant, and the fre- quency of occurrence of species in plots of several sizes, the writer made detailed studies of hill prairie vegetation by means of plot studies in two prairies. He also made studies of some characteristics of all stands from species lists and field notes. Phegley and Sampson Prairies From the 61 hill prairies that he vis- ited, the writer chose Phegley and Samp- son hill prairies for the detailed vegeta- tional studies. These areas are on the same bluff ridge. In their surface fea- tures, Phegley and Sampson prairies are typical of hill prairies. There is a rock ledge and cliff at their base. A stony slope lies above the rock ledge, and loess caps the bluff. Each prairie area possesses spurs and coves. At the time this study was made, prairie covered both the stony 376 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 Fig. 6.— Steep spur front in unpastured Sampson hill prairie, north of Prairie du Rocher, Randolph County, showing some slumping of the loess. August, 1955 EvERS: Hill Prairies of Illinois 377 "^. .^'^ Fig. 7.—Steep spur front in pastured Pliegiey hill prairie, nortii of Prairie du Rocher, Randolph County, showing considerable slumping of the loess. 378 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 and loess slopes. The Phenley prairie was pastured ; the Sampson was not. Thus, it was possible to compare pastured and unpastured prairie slopes in the same locality. Because Phegley and Sampson prairies were accessible to the writer by automo- bile, no laborious and time-consuming ascent from the bottomland, up the basal slopes and over the rcKk ledge, was neces- sary; steep climbs are necessary to attain the majority of hill prairies in Illinois. Study Procedures.—For detailed veg- etation studies in hill prairie, the upper slopes of spurs seemed to be the best sites because these slopes had a vegetation that was nearly "pure" prairie, and they had surfaces that showed little erosion. The steep spur fronts, figs. 6 and 7, contained species characteristic of prairie but showed Fig. 8.—A l-milacre quadrat in the pastured Phegley hill prairie, charted October 9 and 10, 1951, by A. G. Vestal and R. A. Evers. A, Andropogon scoparius; S, Solidago nemoralis; I, Lespfdrza stipularea; B, Boutelntia rurtipendula; G, Gerardia sp. ; P, Pctalostrmtim pur- pureum; H, Houstonia nigricans; D, Desmodium ciliare; L, Lespedeza capitata; E, Euphorbia corollata; f, Cassia fasciculata; ], Junipcrus lirginiana; Is, Linum sulcatum; N, Senecio plat- tensis; v, Pnlygala verlicillata; and d, Hedeoma hispida. August, 1955 EvERS: Hill Prairies of Illinois 379 more or less slumping of loess and, as a consequence, possessed sizable areas with- out plant cover. The more gentle slopes near the bases of the prairies had less se- verely eroded surfaces, and consequently more plant cover, than the steep spur fronts, but they contained more species characteristic of rock ledges. Sizes and Shapes of Study Plots.— A 9-milacre square was staked on the upper slope of a spur of each of the prairies, Phegley and Sampson. These plots were located at some distance from the crest of the bluf¥ in an attempt to exclude forest plants and pasture weeds. Each 9-milacre square was then divided into nine 1-mil- acre quadrats (0.001 acre or 4.046 square meters). The central milacre of the 9- milacre grid was selected for mapping. Each central milacre was divided into UPHILL Fig. 9.—A 1-milacre quadrat in the unpastured Sampson hill prairie, charted October 15 and 16, 1951, by R. A. Evers. A, Andropogon scoparius; Li, Lecidea spp. ; H, Houstonia nigri- cans; D, Desmodium ciliare ; S, Solidago nemoralis; B, Bontrloua curtipendula; G, Gerardia sp. ; P, Petalostemum purpitreum; F, Andropogon gerardi; L, Lespedeza capitata; Av, Agave I'irginica; E, Euphorbia corollata; Op, Opuntia rafinesquii. 380 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 64 small squares of 1 '64 niilacre (ap- proximately 6.25 square decimeters) to facilitate mapping. These small units were combined in workinji; over the data to give 1/16-. 1 4-, and 1-milacrc plots. The central milacre quadrat in the Pheji- ley prairie was mapped, fi^;. 8, and the shoots in this milacre were counted on October 9 and 10. 1^51, by the writer each with an area of 5 milacres and five each of 10 milacres. Species lists were then compiled for the staked areas of each prairie bv units of 1/64. 1/16, 1/4, 1, 3, 5, 9, 10', 25, 50, and 75 (303.5 square meters) milacres. From data obtained from the staked areas, it was possible to determine the number of plant species and number of 33' August, 1955 EvERS: Hill Prairies of Illinois 381 For the three bunch grasses, Andropo- gon SCOparius J A. gcrardi, and Bouteloua curtipendula, the shoots that grew as in- dividuals or in small bunches were counted and recorded. In the Phegley prairie, the shoots were small and mostly distinct and separate. In the Sampson prairie, the shoots were mostly aggregated into "tufts," and these into bunches of varying sizes. In this prairie, A. scoparius occurred also in several large patches within the plots. The number of shoots in such patches was estimated as follows : the average number of shoots per square inch in the smaller bunches was determined by counts ; this number was multiplied by the number of square inches in each of the larger patches. During later stages of preparation of this report, it was evident that an esti- mate of numbers of grass-plant individuals per unit of area could be of great value in finding average plant densities in hill prairies. Other workers have made such estimates. Steiger (1930), in his study of high and low prairies of Nebraska, ap- parently counted each occurrence, whether a single shoot or a bunch, as a grass-plant individual. From the quadrat maps in his report, the bunches of grass appear not so large as those in hill prairies in Illi- nois. Korstian & Coile (1938), in a study of plant competition in forest stands, found the most densely covered forest- floor milacre had about 10 grass plants per 0.01 milacre. "Thus each 0.01 mil- acre occupied by a colony was regarded as fully stocked, even though it contained few or no individual plants." Neither Steiger's procedure nor the one followed by Korstian & Coile seemed adequate for Illinois hill prairies. The estimate of numbers of grass-plant individuals for these prairies was therefore made by a different method. Two bunches of Andropogon scoparius were obtained, one from the Northeast Meredosia prairie, one from the basal slope at Reavis Spring prairie. Each bunch was taken from an unpastured prairie strip that was separated from the adjacent pastured prairie slopes by a fence. These bunches were carefully dissected to find how many shoots were connected by living stems in what might be consid- ered as individual plants. For convenience, each aggregate of shoots considered to be an individual plant was called a tuft. Be- fore separation, each bunch was mapped with a pantograph to show foliage area or crown cover, area at ground surface, lo- cation of solitary live shoots, and what appeared to be aggregates of shoots or "apparent tufts." (It was recognized that separation of a bunch into tufts might give very different results from those of the preliminary surface examination.) It was found that the average number of shoots per tuft of A. scoparius was 3.375 for the Northeast Meredosia sample and 3.793 for the one from Reavis Spring. The characteristic tuft (grass-plant indi- vidual) of A. scoparius was found to be an aggregate of 3 or 4 shoots, average 3.5. The same method was used by H. A. Moore and A. G. Vestal to determine the number of shoots per plant individual for Andropogon gerardi. In a clump of big bluestem, collected by Moore from a rail- road trackway east of Urbana, Moore and Vestal found by separation that the aver- age number of shoots per tuft or grass plant was 1.739. The characteristic tuft (grass-plant individual) of big bluestem consisted of 1 or 2 shoots, average 1.75. As a preliminary step in estimating the number of plants of Bouteloua curtipen- dula, the writer obtained a small sample from Mud Creek prairie and carefully dissected the bunches to determine the number of shoots per plant or tuft. It was found that the average number of shoots per tuft was 3.437; the individual plant of B. curtipendula was an aggre- gation of 3 or 4 shoots, average 3.5. For each of the bunch-grass species, the estimated number of tufts in bunches was found by dividing the number of shoots in bunches by the average number of shoots per tuft, or by a factor based upon this average. Density of Vegetation.—The meas- ure of vegetation density in this study is the number of plants per milacre. The mapped central milacre of the Sampson and that of the Phegley prairie were used in determining density for this report. Grasses.—In the central milacre of the Sampson prairie, 4,051 shoots of Andro- pogon scoparius grew in bunches and patches. The 4,051 shoots formed an es- I 382 Illinois Natural History Survey Bulletin Vol. 26. Art. 5 timated 1,157 grass-plant individuals or tufts. This estimate was reached by di- viding the number of shoots in bunches and patches (4,051) by the number of shoots in a typical tuft (3 or 4, average 3.5). There were in addition 247 shoots not aggregated into tufts or bunches. These were considered individual plants, as it was impossible to determine any un- derground connections without digging and removing these shoots from the mil- acre. The estimated total number of in- dividuals of -:/. scoparius was 1,404. In the Phegley prairie, the shoots of Andropogoti scoparius were mostly short and well separated, with very little lat- eral extension of the foliage. The open appearance of each bunch, the large pro- portion of bare ground, and the consid- erable ground area per shoot within the bunches were attributed to grazing and trampling by cows. Cows doubtless de- stro\ed many shoots either by pulling them out or breaking them off and thus materially reduced the number of shoots per tuft. In the samples taken from ungrazed hill prairie in two sites, Northeast Mere- dosia and Reavis Spring, the number of shoots per tuft averaged between 3 and 4. In the mapped central milacre of the pas- tured Phegley prairie, the number of shoots per tuft was not so large ; it was conservative to place the number of shoots per tuft at one-half that of ungrazed prai- rie, that is, 1.5 or 2.0, average 1.75. The 1,143 shoots in bunches thus formed an estimated 653 tufts or grass-plant individ- uals. In addition, 1^6 isolated shoots, representing that many isolated plant in- dividuals, were counted. The estimated total number of A. scoparius plants was 849. In the mapped Sampson milacre, 22 shoots of Andropogoti gerardi were found; 19 of these occurred in one bunch. These 19 shoots formed 11 plant individuals (estimated). With the 3 isolated plants added, the estimated number of A. ger- ardi individuals was 14. A. gerardi did not occur in the mapped milacre in the Phegley prairie. In the central milacre of Sampson, 6 bunches of Bouteloua curtipendula with 43 shoots w^ere mapped. These 6 bunches contained an estimated 12 plants. In ad- dition, 32 isolated plants were counted. The estimated number of individuals of B. curtipendula was 44. In the mapped Phegley milacre, 15 bunches of Bouteloua curtipendula with 108 shoots were charted. These 15 bunches contained an estimated 31 plants. In addition, 25 isolated plants were counted. The estimated number of indi- viduals of B. curtipendula was 56. The ungrazed Sampson prairie con- tained an estimated 1,462 grass plants in the central milacre ; the grazed Phegley prairie 905 in the central milacre. Table 1 summarizes the above data. Plants Other Than Grasses.—Of plants other than grasses in the central milacre of Sampson prairie, 487 plants of Table 1.—Shoot counts and estimated numbers of bunch-grass plant individuals in the mapped central milacre of Sampson and of Phegley hill prairies. August, 1955 EvERS: Hill Prairies of Illinois 383 Table 2.—Species and numbers of plant in- dividuals in the central milacre of Sampson hill prairie. Table 3.—Species and numbers of plant in- dividuals in the central milacre of Phegley hill prairie. Species 384 Illinois N.atural History Survey Bulletin Vol. 26, Art. 5 estimated ground space covered by these plants was 157.'^ square inches, table 5, an estimation computed in the following manner. There were 29 rosettes of Soli- dago nemoralis that were clustered into five groups or patches. The five patches occupied 3b.59 square inches in the cen- tral milacre. The remaining 241 rosettes of this species were small and covered about 0.5 square inch each, or a total of 120.5 square inches. The total ground space of S. nemoralis for the milacre was 157.09 square inches. The remaining 167 individuals of 13 species were small and averaged only 0.08 inch (2 mm.) in di- ameter, or 0.0049 square inch in area. The estimated ground space of these plants was 0.82 square inch (167 x 0.0049). The estimated ground space for all the nongrass species was 157.9 square inches (10 square decimeters), or 2.52 per cent of the quadrat, tables 5 and 6. The total ground space for all plants in the central milacre at Phegley prairie was 1,403.3 square inches (91 square decime- ters), or 22.37 per cent of the quadrat. There remained 4,869.3 square inches, or 77.63 per cent of the quadrat, that was bare loess, tables 5 and 6. Sampson Prairie.—In the central mil- acre of this unpastured prairie, Andropo- (jon scoparius covered 1,781 square inches (115 square decimeters), or 28.39 per cent of the milacre; Bouteloua curtipen- dula and A. gerardi together occupied 39.3 square inches (3 square decimeters), or 0.63 per cent of the plot, tables 4 and 6. The three bunch grasses covered at ground level 1,820.3 square inches (117 square decimeters), or 29.02 per cent of the milacre. Ihe ground space for the remaining 487 plant individuals of 10 species was computed in the same manner as was the ground space for the plants in Phegley. Lecidea, which grows over the surface of the loess, occupied 29.6 square inches of the milacre as computed from the map by use of a planimeter. The Agave and Opuntia were each about 0.625 inch in diameter at the ground surface; the three plants occupied approximately a square inch. The 64 small rosettes of Solidago nemoralis covered 32.0 square inches (64x0.5). The remaining 248 plants, Table 5.—Ground space or areas (square inches) occupied at ground surface by grass plants, plants other than grasses, and bare loess in the central milacre of Sampson and of Phegley prairies. Type of Plant Growth Bunch grasses Plants other than grasses. . . All plants Bare loess Sampson Prairie 1,820.3 63.8 1,884.1 4,388.5 Phegley Prairie 1,245.4 157.9 1,403.3 4,869.3 Table 6.—Per cent of the central milacre of Sampson and of Phegley hill prairies occupied at ground surface by bunch grasses, plants other than grasses, and bare loess. Species or Type of Plant Growth August, 1955 EvERS: Hill Prairies of Illinois 385 ,tPi^.«'?P'..>- Fig. 11.—Upper .spur slope in uiiiiasturetl ^auiiJMjii lull (uaiiic. The loliage area of the plants is much greater here than in the pastured Phegley prairie. Andropogon scoparius is the dominant grass; A. gerardi also is present. The above view is to the left (northwest) of plots stalled for vegetation studies of this report. at-J • <,»#-»«£ i^-. ""r-'-.id)'"'- . .^^ Fig. 12.—Upper spur slope in the pastured Phegley hill prairie. The foliage area of the plants is small. Andropogon scoparius is the dominant grass. To the right in the above view is a small part of some of the plots staked for the vegetation studies of this report. 386 Illinois N.atural History Survey Bulletin Vol. 26. Art. 5 Table 7.—Foliage area (square inches) for plants in the centra! milacre of Sampson and of Pheiiley hill prairies. Species or Type of Plant Growth August, 1955 EvERS: Hill Prairies of Illinois 387 Table 9.—Available space per plant in the central milacre ot Sampson and of Phegley hill prairies. Hill Prairie 388 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 each and averaged 11.5. The average number of plants was 335.25 in this size unit. In the 9-milacre square, the species list compiled by 1/4-milacre units showed a range of 6 to 12 species and an average of 9.27 per unit. The 1-milacre plot size had a range of 1 1 to 16 species each and an average of 13.44. Ten species not found in the central milacre but found in the surrounding eight were A ndropogoii gerardi, Lecidea sp., Aster patens, Eragros- tis spectabilis, Rhus copallina, Kuhnin eu- patorioides, Panicum scrihrierianum , Poa pratensis, Ruellia humilis, and a second species of Gerardia (possibly G. aspera) . Twenty-six were found in the 9-milacre quadrat. The 9-milacre plot formed a part of the staked 50-mi!acre rectangle, fig. 10, which was examined b\ 10-milacre strips. Six species not found in the 9-milacre square were found in other parts of the rectangle. These were Aster oblongi- folius, Optiutia rofiiiesquii, Tridens flavus, Melilo/us alba, Rhus arornatica, and Eri- geron strigosus. The first four of these were found only in the 10-milacre strip nearest the improved pasture eastward from the crest of the ridge. This strip, because of its proximity to the pasture, probably should not be considered typical hill prairie. Two species not found in the 9-milacre plot were found in other parts of the four downslope 10-milacre strips and brought the total to 28 species. The 25-milacre quadrat downslope from the 50-milacre rectangle yielded but one species that did not occur in the 50- milacrc rectangle ; this was Asclepias vir- idifiora. There were, however, seven spe- cies in the four downslope 10-milacre strips of the 50-milacre area that did not occur in the 25-milacre unit. These were Rhus copallina, Kuhnia eupatorioides, Panicujn scribnerianum, Poa pratensis, Table 10.—Frequency of occurrence of plant species in plots of five sizes, Sampson hill prairie. Species Andropogon scoparius . . . Houstonia nigricans Desmodium ciliare Solidago nemoralis Lespedeza capitata Gerardia gattingeri{ ?) . . . Bouteloua curtipendula. . . Lecidea spp Andropogon gerardi Petalostemum purpureum Senecio plaltensis Euphorbia corollata Agave virginica Opuntia rafinesquii Aster patens Carya sp Sisyrinchium albidum . . . Unidentified moss Size A fl/256 Milacre, 0.0156 Square Meter) Num- ber of Plots 60 22 19 13 1 1 12 4 Per Cent of Plots 93.8 34.4 29.7 20.3 1.6 1.6 18.5 6.3 1,6 3.1 to species 64 plots Size B (1/64 Milacre, 0.0625 Square Meter) Num- ber of Plots 64 49 42 32 5 11 17 Per Cent of Plots 100.0 78.1 65.6 50.0 7.8 17.2 26.6 12.5 4.7 12.5 1.6 3.1 1.6 13 species 64 plots Size C (1/16 Milacre, 0.25 Square Meter) Num- ber of Plots 16 15 16 15 5 Per Cent of Plots 100.0 93.8 100.0 93.8 31.3 50.0 56.3 50.0 12.5 43.8 6.3 12.5 6.3 13 species 16 plots Size D (1/4 Milacre, 1.01 Square Meters) Num- ber of Plots 36 36 33 33 24 20 18 15 14 13 7 7 2 2 \ 1 1 1 Per Cent of Plots 100.0 100.0 91.7 91.7 66.7 55.6 50.0 41.7 38.9 36. 19. 19. 5. 5. 2. 2. 2. 2. 18 species 36 plots Size E (1 Milacre, 4.05 Square Meters) Num- ber of Plots 9 9 9 9 9 9 8 7 6 7 4 5 2 2 1 1 1 1 Per Cent of Plots 100 100.0 100 100 100 100 88.9 77.8 66.7 77.8 44 4 55. 22. 22. 11 11 11 11 18 species 9 plots August, 1955 EvERS: Hill Prairies of Illinois 389 Hedeoma hispida, R. aromatica, and Gcr- ardia (possibly G. aspera) . The 75-mil- acre unit minus the 10-milacre border strip contained 29 species. The 75-mil- acre unit contained 33 species. Frequency of Occurrence of Spe- cies.—The frequency, or repeated occur- rence, of plant species in Phegley and Sampson prairies was determined from species lists of each of the following plot sizes: 1/256-, 1/64-, 1/16-, 1/4-, and 1 -milacre. Although the 1/256-milacre unit was not marked in the field, data for plots of this size were obtained from maps of the mapped central milacre of both Sampson and Phegley prairies, figs. 8 and 9. On such maps the northwest quarter of the milacre was divided into 64 equal quadrats and, from these, species lists were compiled. The metric equivalent of this quadrat size is 0.0156 square meter. For any given plot size the frequency was ex- pressed as a percentage computed by divid- ing the number of quadrats in which the species occurred by the total number of quadrats of that size employed. Sampson Prairie.—Table 10 summa- rizes the data for the frequency study in unpastured Sampson prairie. It is evi- dent that the 1/256-milacre size was too small for use in ecological studies of Illi- nois hill prairies; only one species, Ati- dropogon scoparius, attained a high per- centage of occurrence. The 1/64-milacre Table 11.—Frequency of occurrence of plant species in plots of five sizes, Phegley hill prairie. Species 390 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 size in Sampson was more nearly ade- quate than the 1 256-milacre size in this unpastured prairie; 4 species of the 13 found in the 64 plots of the 1 ''64-milacre size attained a percentage of 50 or more. These 4 species represented 30.77 per cent of the numher of species found in the 64 plots. .:/. scoparius occurred in all the quadrats of the 1 ^64-milacre size. It is evident that the 1/16- and the 1/4-milacre plots (C and D in table 10) gave good Frequency Values for Combina- tions of Species.—In Sampson and Phegley prairies, certain species of plants occurred together in so many plots as to call attention to the combinations. In Sampson, the species in combination were Andropogon scoparius, Solidago nemoralis, Houstonia nigricans, and Desmodium cil- iare. In Phegley, they were Andropogon scoparius, Solidago nemoralis, Desmodium ciliare, and Bouteloua curtipendula. The Table 12.—Frequency of occurrence of characteristic combinations of plant species, Samp- son and Phegley hill prairies. August. 1955 EvERs: Hill Prairies of Illinois 391 pie in one study known to the writer : the forest studv bv Vestal & Heermans (1945)._ Species-Area Curve.—A species-area curve can be constructed from data ob- tained from the species list for the various plot sizes. The maps of the central mil- acres, figs. 8 and 9, furnished the data for deriving average numbers of species in quadrats of 1 256-, 1/64-, and 1/16-mil- acre sizes. Species lists, compiled by 1/4- milacre units, for each of the 9-milacre squares furnished the data for computing the averages for quadrats of 1/4- and 1- milacre sizes. The total number of spe- cies found in the 9-, 25-, 40-. 50-, 65-, and 75-milacre areas provided the figures for the larger plot sizes. These data are shown in table 13. When the data are plotted on semiloga- rithmic paper, the resulting curves are S-shaped, fig. 13. From this type of curve, certain reference areas can be determined with the method described by Vestal (1949). These are (1) the smallest rep- resentative area, (2) the minimum area for assignment to type, after this referred to briefly as minimum area, and (3) the Table 13.—Numbers of plant species in plots of various sizes, Sampson and Phegley hill prairies. 392 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 and a moderate number of minor species, is an area 5 times as large as the smallest representative area and usually contains 1.44 to 1.5 times as many species. It is the smallest size to be used if a single one- piece sample is to be examined. The fair- sized stand (Af) is an area 50 times as large as the smallest representative area and contains twice as many species. For Sampson prairie, the curve indi- cates the smallest representative area to be 0.76 milacre, with 10.8 species; the computed minimum area 3.80 milacres, with 15.6 species, or 1.444 times as many species as in the smallest representative area; the fair-sized stand 38.0 milacres, with 21.6 species. For Phegley prairie, the curve indi- cates the smallest representative area to be 1.26 milacres, with 14.3 species; the computed minimum area 6.30 milacres, with 21.4 species, or 1.497 times the num- ber in the smallest representative area ; the fair-sized stand 63.0 milacres, with 28.6 species. The 9-milacre square was larger than the smallest representative area and mini- mum area for both prairies. Both prairies were of more than sufficient size to qual- ify as fair-sized stands. The number of species in 1 acre was estimated to be 28.0 in Sampson and 35.2 in Phegley. Summary of Pastured and Unpas- tured Prairies.—Some of the differences in vegetation of the pastured and the un- pastured hill prairies are here summarized. 1. The number of species in a quadrat was larger in the pastured than in the un- pastured hill prairie. 2. Plant density, based on the number of plants in a quadrat, was smaller in the pastured than in the unpastured prairie; the grass bunches were smaller, less vig- orous, and not so tall. 3. Grasses constituted a smaller per- centage of the total number of individual plants in the pastured prairie than in the unpastured. 4. The ground space occupied by grasses was smaller in the pastured prairie than in the unpastured. 5. Foliage area, or crown cover, was understandably much smaller in the pas- tured than in the unpastured prairie. Also, the ratio of crown cover to ground space was smaller in the pastured prairie than in the unpastured prairie. Vegetation Characters From Other Stands In the preceding section, some analytic characters of vegetation were described for two hill prairie stands, Sampson and Pheg- ley prairies. Analytic characters of vege- tation, according to some phytosociologists, are those traits which are studied in each stand. Synthetic characters of vegetation are those which are studied from compari- sons of large numbers of stands. Presence, a synthetic character of vegetation, and seasonal aspect, also synthetic in that it was described from observations made on most of the stands of Illinois hill prairies, are here briefly presented. Presence.—Presence, as used here, is defined as the more or less persistent oc- currence of a species in the stands of a plant community. Used for this study were 36 stands of hill prairies that the writer visited at least twice during the field work. From species lists of the 36 stands, a table was devised which lists the species and the stands in which they oc- curred, table 14. Species of forests or thickets and those of foreign origin were not included in the table unless they oc- curred in 18 or more of the stands. Three species were present in 90 per cent or more of the stands. They were Andropoffon scopariuSj Ei'igeron strigosus, and Bouteloua curtipendula. Six species were present in 80 to 89 per cent of the stands. They were Petalostemum pur- pureum, Euphorbia corollata, Penstemon palUdus, A. gerardi, Verbena stricta, and Kuhnia eupatorioides. These nine species were the "constants" of the association ; they can be classed as "constantly pres- ent." The "commonly present" species, that is, those present in 60 to 79 per cent of the stands, were Eupatorium altissi- mum, Rhus glabra, Oxalis violacea, Soli- dago nemoralis, Panicurn scribnerianum, Aster oblongifolius, and Ruellia humilis. Species in 50 to 59 per cent of the stands were Linum sulcatum, Lithospermum in- cisum, Melilotus alba, Lespedeza capi- tata, Pycnanthemum pilosum, Poa pra- tensis, Psoralea tenuiflora. Cassia fascicu- August, 1955 EvERS: Hill Prairies of Illinois 393 lata, and Sorghastriun nutans. Thus, in 50 per cent or more of the hill prairies, there were 25 species present. All are na- tives of North America except one, possi- bly two. Melilotus alba is Eurasian. Poa pratensis is generally considered European by many authorities, but Gleason (1952) states, "In most of our range introduced from Europe; along our n. boundary and in Canada it may be native." It might prove difficult to determine whether Illi- nois plants of this species had their origin in Europe or Canada. Species most characteristic of the hill prairie type are Bouteloua curtipendula, Psoralen tenuiflora, Petaloste?nuni can- didum, Linu/n sulcatum, and Lithosper- mum tncisutn. The presence of these spe- cies in other prairie types in Illinois is much lower than in hill prairie. Seasonal Aspect.—The Illinois hill prairies studied in the years covered by this report showed certain seasonal as- pects. In winter, the brownish color of the grass cover predominated. On some un- grazed hill prairies, tall grass stems of the previous growing season bent over and trended downslope to form a fairly com- plete cover over the soil. Small purplish rosettes of Solidago nemoralis and green rosettes of Senecio plattensis were evident between the grass clumps in some of the prairies. The prevernal aspect was mostly brown. In early April in some prairies, the small white flow^ers of Draba reptans were seen. By late April, the violet flow- ers of Oxalis violacea, the yellow-orange blossoms of Lithospermum canescens, and the yellowish flowers of Salix humilus and Rhus aromatica were evident among the grass bunches. In the vernal phase, the dominant color changed from brown, through brownish- green, to green as the grasses began their growth. Hedeoma liispida, with very small bluish blossoms, was common in the interspaces in many prairies. Ei'igeron strigosus, taller than the grasses during the vernal phase, was very conspicuous with its white flowers, as was also Pen- stemon palUdus. Tradescantia, with pur- ple blooms raised above the level of the grasses, was scattered in many prairies. The yellow rays of Senecio plattensis and Coreopsis lanceolata were conspicuous in some. Several grasses, Panicum scrib- nerianum, Poa pratensis, Festuca octo- flora, and Koeleria cristata, flowered at this time. In the aestival stage, the predominating color was green or purplish-green. Echi- nacea pallida, with purplish rays, was in bloom, and Linum sulcatum, with small yellow petals, began its flowering. In some prairies the small whitish flowers of Houstonia nigricans were frequent. The inflorescences and foliage of Psoralea tenuiflora gave some prairies a purplish- green hue, especially in early July. The purple-flowered Buchnera americana and Petalostemum purpureum and the white- flowered prairie-clover, P. candidum, were scattered in some prairies. In late June and early July, the green or purplish- green inflorescences of Bouteloua curti- pendula appeared. In the latter part of July and early August, the bronze, green, or purplish-green inflorescences of An- dropogon scoparius and A. gerardi were conspicuous. By late August, the yellow of Solidago nemoralis and the purple of Liatris aspera were evident. In the autumnal phase, beginning in September, the dominant color changed from green to brownish hues. The yel- low rays of Solidago nemoralis and the white or purple rays of several species of Aster were common. By October, very few plants, an occasional Solidago or a Houstonia, or, less often, a Spiranthes, were still in flower. By November the prairie was again dormant; the dominant grass cover was brown. VEGETATIONAL HISTORY AND SUCCESSION The vegetational history of Illinois, a state that is within the area of overlap of eastern prairie and forest, is deduced mainly from circumstantial evidence. The evidence is derived from the present flora and vegetation, especially from apparent relict colonies, from fossils in the loess, and from analyses of pollens and fossils in peat and lacustrine deposits. Deductions must conform not only to the facts of bot- any but also to the facts of meteorology 394 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 and geology. In making deductions con- cerning plant succession and vegetational history of Illinois hill prairies, it is nec- essary to keep in mind some of the Pleis- tocene history of the area in which these prairies occur. The strip of land along the present Mississippi River valley in western Illi- nois has had a vegetational cover since Kansan glacial times, fig. 4, except for the portion from southern Carroll Coun- ty to northern Adams County, inclusive, which was covered by ice during part of lUinoian glacial time. Except for a strip between Fulton, Whiteside County, and Cordova, Rock Island County, which was covered during Tazewell glacial time (Shaffer 1954), the entire western border has supported a plant cover since Sanga- mon interglacial time. It was during Tazewell time that the present valley of the Mississippi from the Rock Island area south to Adams County was established. The eroding valley perhaps did not main- tain a continuous plant cover but the ad- jacent uplands did; their cover was prob- ably prairie. The Illinois River valley south from the "Big Bend" at De Pue was established in pre-Pleistocene time and has been occu- pied by vegetation since Illinoian deglaci- ation except for the area from Peoria northward, which was glaciated again during Tazewell time. The Rock River hill prairie site included in this report was not covered by ice after Farmdale glacial time. The area along the valley of San- gamon River near its mouth was last gla- ciated during Illinoian time. It seems entirely possible that during the Tazewell substage, when the ice-front was at the Shelbyville moraine, a fairly steep climatic gradient prevailed, with cli- matic conditions along the valleys in western Illinois not very different from those of the present. Loess deposition oc- curred during the time of advance, maxi- mum extent, and recession of the glacial ice. The major deposition doubtless took place in the autumn and winter, which were then, as now, the dry seasons of the year. Loess deposits of Kansas contain fossil snails that point to a plant cover for that area at the time of deposition that consisted of shrubs and herbaceous spe- cies (Leonard 1952) and of a forest bor- 1 der near the Missouri River (Leonard & \ Frye 1954). As the Kansas deposits are of comparable age to those of Illinois, a similar plant cover may have existed in parts of Illinois. The vegetation in much of western Illinois west of the Tazewell ice-front may be imagined as that of a prairie or grassland (Gleason 1923). The floodplains were devoid of plant cover be- cause of the constant shifting of the over- loaded streams with their braided chan- nels. During the drj' autumnal and win- ter seasons, the floodplain served as a source of silt, which was transported to the uplands by the then, as now, prevail- ing northwest winds. While separating bunch-grass clumps from Reavis Spring to expose individual plants (page 381), Vestal and the writer observed that vigorous upward growth of plants had kept pace with the deposition of additional sandy material. From such observations it can be concluded that, along the bluffs, deposition of loess fa- vored rather than discouraged the growth of bunch grasses. The inverse also was true ; a grass cover favored the catching and holding of windblown silts (Shimek 1903). As new areas were exposed by deglaciation (for instance in the Putnam County hill prairie locations), the prairie species, because of proximity and the ra- pidity with which many of them could become established, moved in and occu- pied the bluffs before woody plants could do so. Mosses and lichens were not the first plants to become established in areas of deglaciation. On present-day loess and till slopes in Illinois, these cryptogamic species are absent from sizable areas without vascular plants but are present in some interstices where grass plants give some protection. A similar situation prob- ably prevailed during deglaciation. Prai- rie vegetation thus can be assumed to have long antedated tree cover on many of the bluffs of the larger rivers in Illinois. The advantage of priority of occupation is probably far more important in succes- sion than is commonly realized. Although subsequent history has per- haps been one of progressive encroachment by forest on many of the Illinois bluffs, especially those of low altitude, several August, 1955 EvERS: Hill Prairies of Illinois 395 stretches of bluff frontage, totaling 25 to 30 miles, remain hill prairie or are in part hill prairie. Possibly as much as three times this extent, 75 to 90 miles, or about one-eighth of the bluff frontage on the east sides of the major stream valleys, was prairie in the early nineteenth century, but was converted to pasture or otherwise dis- turbed by the activities of man. The bases for such an estimation are the few scat- tered prairie plants along stretches of bluffs now occupied principally by blue- grass and numerous pasture weeds. Such stretches of bluffs are common along the Mississippi River in Jo Daviess County. Doubtless these bluffs were prairie cov- ered in the not distant past. Hill prairies have been surprisingly successful in resisting destruction by the grazing of domestic animals and by some of the activities of man. There are no records to show how heavily these prairies were grazed by bison before the arrival of ivhite men in Illinois. It is possible that bison grazed many hill prairies, but that they failed to reach some that were hid- den by surrounding dense forest. Whether or not pastured hill prairies observed for this report are being reduced by overpas- turing is not yet evident. Goat pasturing in one site along the bluffs of the Illinois River south of Rosedale caused complete destruction of the prairie, leaving only bare loess on the slope. The spread of residential and industrial areas has de- stroyed some of the hill prairies. On the other hand, it is evident that fire has not destroyed them ; seemingly, it has per- mitted an earlier and more tender growth of grass. What is the probability that hill prairies are now being invaded by forests? Some of the most typical hill prairies are located on brow slopes where the cliffs are so high that they extend above the trees that grow on the toe slopes ; without the shade of the trees, the brow slopes, especially those facing southwest, are exposed to the heat of the sun and to the prevailing winds of summer and are thus too xeric for grow^th of mesophytic forest and will probably remain prairie. The bluff coves, which serve as drainageways on the slopes, are more mesic and, in places, support mixed forest. Such forested coves contain tree species that are found in the forests of the basal slopes, of the slopes of the tributary valleys parallel to the main valleys, or of the uplands. Where the bluffs are low, or in the few places where the ascent from floodplain to upland is continuously of low gradient, trees have long shaded the upper slopes and greatly reduced wind movement. In such situations, forests have been established over entire slopes. In years of abundant rainfall, forest seedlings become established on prairie spurs, only to die in years of less abun- dant rainfall or in periods of successive dry years, as of the 1930's. Dwarfed trees, as w^ell as dead sumacs and red ce- dars, are reminders of dry years and a contest between forest and prairie. It thus seems probable that a shifting equi- librium was long ago reached between prairie and forest, especially on bluffs with high cliffs. As long as the present topography and climate persist, such hill prairies will remain approximately as they are. Delimitation and description of the actual stages of succession within hill prai- rie areas cannot be made now, but must await the advent of interested botanists of the future. In the interim, it is im- portant that botanists continue the study of these sites and publish the results of their studies. From such studies, bota- nists will be able to trace actual, not hypo- thetical, paths of succession and also de- duce with a greater amount of accuracy the past vegetational history. ANNOTATED LIST OF HILL PRAIRIES The following list of Illinois hill prai- ries includes only those prairies which the writer visited during the field work for this study. The name given to each of the prairies was derived from one of sev- eral sources—the name of the landowner, or of the tenant, or of the farm on which the prairie was found ; the name of that stretch of bluff occupied by the prairie; or the name of some nearby landmark or community as applied locally or found on a quadrangle of the United States Geo- logical Survey topographic map. Loca- tion of each prairie is given according to 396 Illinois Natural History Survey Bulletin Vol. 26. Art. 5 section, town, and range except for prai- ries within municipalities, state parks, or the old French land ti:rants. These grants extended inland at right angles to the bank of the Mississippi River and were not surveyed according to the township sys- tem. In this hill prairie study, such grants were encountered in Monroe and Randolph counties. For con\enience in listing, the prairies are divided into three groups, (a) those along the Mississippi River from East Dubuque to Grafton, (b) those along the Rock. Sangamon, and Illinois rivers, and (c) those along the Mississippi River from Grafton to Cairo and elsewhere in southern Illinois. On the bluffs south of Warsaw. Hancock County, were several small openings which were seen but not examined for this study. Also, on the south side of the lower Sangamon River valley were a number of hill prairies, some with north- and northwest-facing slopes. Many of these prairie slopes served as pastureland and were much disturbed. Some of the slopes were completely con- verted to bluegrass pastureland. None of these slopes was visited. Fig. 1 shows the locations of these hill prairie sites. Not described, nor indicated in fig. 1, are sev- eral pastured grass slopes on the bluffs of the Mississippi River, west and south of Galena, Jo Daviess County, which were visited June 15-16, 1950. At that time they were covered with many weeds and they contained few prairie plants. East Dubuque to Grafton El Rancho.—This prairie, located on the bluff above the El Rancho Cafe in East Dubuque, Jo Daviess County, was visited July 16 and October 4, 1950; May 9 and June 14, 1951. Prairie, slightly over an acre in area, covered the stony part of the slope above the cliff, and also the loess on that part of the slope above the stony part. The uppermost part of the slope and the generally flat bluff- top, greatly disturbed by the WPA in constructing stone foundations for a fire- place and two shelters, had been much trampled and was weedy. Two Indian mounds crowned the spur nearest the cafe. A forested cove separated this spur from another to the south. Three Indian mounds occupied the crest of the southern spur. A ndropoyon scoparius was the dom- inant grass of both spurs; Stipa spartea grew in large patches on the south spur and was in smaller, scattered patches on the north spur. Menominee Station.—This prairie, in the southwest quarter of section 17, T. 27 N.. R. 1 W., on the bluffs of the Mis- sissippi River, about one-half mile south- east of Menominee Station, Jo Daviess County, was visited October 4, 1950; May 9 and June 14, 1951. Prairie cov- ered about 4 acres on parts of four south- west-facing spurs. Rock fragments cov- ered the surface for a few yards above the rock ledge; loess capped the bluff. An- dropoijon scoparius was the dominant grass. The northeast-facing slope of the northernmost spur and the uplands ad- joining the remaining spurs supported a mixed forest. Rhus glabra formed dense stands on three spur-tops, and it extended downslope on the north sides of these spurs. Populus tremuloides occupied a part of the crest of the northernmost spur of this prairie. North Savanna.—Prairie covered the upper southwest- and west-facing slopes of the bluff-ridge in section 21, T. 25 N., R. 3 E., 3 miles north of Savanna, Car- roll County, when the site was visited June 14, 1951. On the slopes above the rock ledge, Bouteloua hirsuta was abun- dant. Disturbed prairie covered the crest of the ridge. Northward along the ridge, the slope and top were occupied almost en- tirely by Juniperus virginiana. Sunset Trail.—At the time this study was made, prairie occupied one northwest- facing spur, three west-facing spurs, and one south- to southwest-facing spur on the bluff north of the Administration Building in the Mississippi Palisades State Park, north of Savanna, Carroll County. A trail. Sunset Trail, crossed parts of this prairie. Andropogon sco- parius and Bouteloua curtipendula were abundant grasses. Sandy loess covered the northwest- and west-facing slopes ; the south-facing slope was stony. The stony slope was not so steep as the loess slopes. These spurs were visited October 4, 1950, and June 14, 1951. August, 1955 EvERs: Hill Prairies of Illinois 397 Hill-Top.—This prairie opening, when examined October 5, 1950, occupied about 4.5 acres on the uppermost surface of the bluff, one ravine south from the main entrance to the Mississippi Palisades State Park. A mixed forest surrounded the prairie. Sor-ghastrum nutans was the dominant grass ; Panicum virgatutn was abundant. Several paths crossed the prai- rie. Here and for a short distance into the prairie, weeds were common. South Palisades.—This prairie occu- pied about 0.2 acre of the generally stony southwest-facing ridge-slope north of the abandoned quarr}- near the southern boundary of the Mississippi Pali>ades State Park, when observations were made there on June 22 and October 5, 1951. Andropogon scoparius was the dominant grass. Bielema.—Prairie occupied slightly more than an acre of the bluff on the Bie- lema farm in section 32, T. 23 N., R. 4 E., southeast of Thomson, Carroll County, in 1950. Stones strewed the lower slope ; sandy loess comprised the upper. The base of the lower slope, much disturbed by pigs, was weedy. Prairie, with Bouteloua curtipendula and Andro- pogon scoparius as dominant grasses, cov- ered the upper part of the rocky slope. Andropogon scoparius was the dominant grass on the sandy loess, except where shallow drainageways on both the stony and loess slopes were densely covered by Artemisia caudata. Poa pratensis was the dominant cover on the northern part of the bluff-top; Bouteloua curtipendula dominated the southern part of this sur- face. Bielema prairie was visited June 23 and October 6, 1950. Balk.—In 1951, two conspicuous prai- rie openings, together about 1 acre, were observed on the upper west-facing slope of the bluff-ridge in section 5, T. 22 N., R. 4 E., in Whiteside County. The south- ern opening and the surrounding forest were frequented by pigs ; the northern opening, which was separated from the southern by a fence, was unpastured. Bou- teloua hirsuta and Stipa spartea occurred in these openings. This site was visited June 13, 1951. Wiersma.—Hill prairie, about 0.5 acre in area, occupied the upper west-facing slope of the bluff-ridge on the Wiersma farm in section 8, T. 22 N., R. 4 E., Whiteside County, in 1950. Bouteloua curtipendula was apparently the dominant grass; Andropogon scoparius was locally abundant. The entire ridge was heavily pastured. Wiersma prairie was visited October 6, 1950. Rock Island 31.—This site, located in section 31, T. 16 N., R. 5 W., Rock Island County, was visited September 9, 1949. The slope, heavily pastured, and covered with a mixture of prairie and for- est, was stony below and capped with sandy loess. Andropogon scoparius, A. gerardi, Sorghastrurn nutans, and Boute- loua hirsuta were some of the grasses on this slope. Bald Bluff.—The name denotes the prominent, narrow, northwest-projecting arm of the Mississippi bluffs in section 18, T. 12 N., R. 4 W., Henderson Coun- ty. Mantled with sandy loess, Bald Bluff supported both mixed forest and prairie when visited. This prairie, with an abun- dance of Bouteloua hirsuta and many weedy species, was heavily pastured. Prai- rie covered about 9 acres, 3 of which were examined on August 18, 1951. Ursa.—When visited, this hill prairie occupied the southwest- and west-facing slopes on the north side of Ursa Creek valley where the creek enters the Missis- sippi River bottomland in section 13, T. 1 N., R. 9 W., Adams County. Prairie covered about 1 acre of the slopes. A stony levee and small spring-fed stream separated the road on the west from the bluff to the east. The stony east bank of the stream supported prairie. Small rock outcrops capped the stream bank. Above these outcrops the surface was al- most level. A dense stand of Juniperus virgin-ana with scattered individuals of Quercus muhlenbergii and Cornus drum- mondi grew on the level surface near the limestone outcrops. Eastward there was a narrow belt of prairie and beyond that a thicket which included small oaks, bass- wood, and hop hornbeam. This thicket bordered the base of a steep loess spur which was covered by prairie up to the top of the bluff. Prairie covered the southwest-facing spurs, mixed forest the coves. The bluff-top was a mixture of 398 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 prairie and sumac. Ursa prairie was vis- ited August 11 and September 9, 1950; June 2 and July 14, 1951. Rock Greek.—Located north of Rock Creek, in the northwest quarter of sec- tion 25, T. 1 N., R. 9 W., Adams Coun- ty, this prairie when visited covered more than an acre of a ridge of sandy loess. Andropogon scoparius was the dominant grass; A. tjerardi and Bouteloua curtipen- dula were present. Asclepias stenophylla and Chtnopodiiim leptophylluin occurred in the interspaces. Fsoralea ienuiflora was common on the gentle lower slope and the almost level top, but was infre- quent on the steeper slopes. Rock Creek prairie was visited September 8, 1949; August 11, 1950; April 25, June 2, and July 14. 1951. _ Homan.—This name, which is also the name of the creek to the east, here designates the small hill prairie that in 1951 occupied slightly more than an acre in section 11. T. 1 S., R. 9 W., about 3 miles north of Quincy. Prairie covered the west- and southwest-facing slopes of the southern tip of a ridge that ends at Homan Creek. The crest of the ridge was almost covered with Rhus glabra, Psoralen tenuifiora, Petalostemum can- didum, and Melilotus alba. A few indi- viduals of Asclepias stenophylla and Del- phinium Carolinian urn occurred there as well as on the slopes. Vegetation of the east-facing slope was principally a mix- ture of prairie and sumac. Andropogon scoparius dominated the west- and south- west-facing slopes. Bouteloua curtipen- dula occurred in scattered patches. This site was visited on April 25, June 2, and July 16, 1951. Parker Heights.—This small hill prairie, which occupied the south part of a ridge in Parker Heights, a park about a mile north of Quincy, Adams County, was visited May 28, 1950, and July 16, 1951. Disturbed prairie, much trampled by people, covered the west- and south- west-facing slopes above the exposed limestone bedrock. Hidden Lake.—The pond within the quarrv in the southeast quarter of sec- tion 23, T. 2 S., R. 9 W., about 2 miles south of Quincy, provided the name for this site. A wall of limestone which forms the north and east limits of the lake is covered with a thick mantle of loess to form the bluff. Above the bedrock, the mantle of loess forms an almost vertical cliff with heights to 15 feet, and above the loess clif¥ is the gentle west- and southwest-facing brow slope of the bluf^. Hidden Lake prairie, when visited Sep- tember 8, 1949, and May 28, July 2, Au- gust 13, and September 9, 1950, covered about 0.2 acre of this slope. The steep loess face was almost without vegetation except at its junction with bedrock. Small shrubs occupied this junction. The prairie had been much disturbed by human tram- pling, because the site attracted numerous boys from nearby Quincy. Andropogon scoparius was dominant on the slopes. A dense stand of Rhus glabra, Melilotus alba, and A. scoparius occupied the crest of the ridge. Tridens flavus was fre- quent. Seehorn Cemetery.—This prairie, lo- cated on the uppermost slope of the bluff, in the southeast quarter of section 26, T. 3 S., R. 8 W., Adams County, was vis- ited September 9, 1950. Prairie occupied the cemetery and some of the slope to the northwest and southeast. Downslope there was a mixed forest; upslope a bit of prairie was found between the cemetery and the cultivated upland. Sorghastrum nutans was the dominant grass. Andro- pogon gerardi, Bouteloua curtipendula, and Psoralea tenuifiora were common. Fall Greek.—This prairie in 1950 oc- cupied the bluff about one-quarter mile south of Seehorn Cemetery prairie. Mixed forest occupied the coves; forest, or a mixture of prairie and forest, covered the spurs. Andropogon scoparius, A. gerardi, and Sorghastrum nutans appeared equally abundant. Interspaces between the bunches of grass were small. This area was visited September 9, 1950. North Pandarmie.—This name des- ignates a group of spurs and coves on the bluffs in section 31. T. 3 S., R. 7 W., and section 36, T. 3 S., R. 8 W., north of Pandarmie Hollow, 2.5 miles south- east of Fall Creek, Adams County. When North Pandarmie was visited Sep- tember 9, 1950, forest occupied the coves; a mixture of prairie and forest covered the spurs. Andropogon gerardi and Sor- August, 1955 EvERS: Hill Prairies of Illinois 399 Fig. 14.—Housen hill prairie, north of Rockport, Pike County. The forest of the basal slope extends to the bluff top through the drainageway at the left of the prairie. ghastrurn nutans were abundant; A. sco- parius was infrequent. At the top of the brow slope was a strip of woodland. Its northeast side had a dense border, 3 to 6 feet wide, of Sorghastrum. At the base of the spurs, Mentzelia oligospernia grew in the crevices of the interrupted rock ledge. Seehorn-Payson.—The name of this hill prairie comes from a village in Pike County and a township in Adams Coun- ty. In 1950, prairie occupied about an acre of slope ; part of this area was in the southwest quarter of section 31, T. 3 S., R. 7 W., Adams County, and part in sec- tion 6, T. 4 S., R. 7 W'., in Pike County. Astragalus distortus occurred on the loess and on the rock ledges. Mentzelia oli- gospernia grew on the rock ledges and the rocky slope above the ledges. The prairie was heavily pastured by cattle and sheep. Poa pratensis was the most abundant grass on the prairie slopes; A ndropogon scopa- rius was infrequent. In September, 1950, very little of the herbaceous vegetation was more than 6 inches tall ; the average was 3 to 4 inches, except for an occa- sional bunch of Bouteloua curtipendula. This prairie was visited May 28, July 2, and September 9, 1950. Sessions.—In the 3 years this hill prai- rie was under observation, it occupied about 4.5 acres of the upper southwest- and south-facing slope of the bluff in sec- tion 5, T. 5 S., R. 6 W., on the Sessions farm between Kinderhook and New Can- ton in Pike County. Prairie covered seven spurs, mixed forest the intervening coves. Above the rock ledge was a stony slope covered with prairie. Loess mantled the bluff. There was a generally flat upland to the northeast of the slope. Prairie cov- ered the almost flat spur-tops and some of the flat upland to the northeast. Much Rhus glabra grew on this flat surface and at the heads of the south-facing coves. A ndropogon scoparius was the dominant grass. The entire site served as a pasture. Visits were made to Sessions hill prairie on September 7, 1949; May 28, July 2, September 8, 1950; and April 24, 1951. South New Canton.—A small hill prairie, less than 1,000 square feet in area, in 1950 occupied the southwest-facing bluff slope southeast of Morey Cemetery, about a mile southward along the blufifs from New Canton, Pike County. A rocky slope lay above the rock ledge, and loess capped the bluff. A ndropogon scoparius was the dominant grass. Mentzelia oli- gospernia grew abundantly in the crevices and recesses of the ledge and infrequently on the lower part of the loess slope. The entire blult and the upland ridge to the 400 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 northeast was pastured and much dis- turbed. X'isits were made to this site on May 27, July 1. and September 8, 1950. Housen.—When visited April 24, 1951. this hill prairie in the southeast quarter of section 7, T. 6 S, R. 5 W., on the Housen farm north of Rockport, Pike County, covered more than an acre of the uppermost southwest-facing slope of the crest of the ridge grew a mixture of prai- rie, woodland, cultivated plants, and weeds. Some of the plants growing in this site were Lespcdeza stipulacea. Syrnphori- carpos orhi( ulatits, Mclilotus alba, Tri- dcns flavus. Boutcloiia curtipendula, A n- dropogon scoparius, A. gerardi. Verbena stricta, and Eragrostis ciUanensis. The inner, or northeast, slope of the ridge sup- ^^.^.•k. f .A IWfLi^k. J'^.^1^ Hfc' :^ L.-1* VA" .• ^.'•.Vu-•• *^. rip- Fig. 15.—The Clendenny hill prairie, northwest of Bellevievv, Calhoun County. Buchnera americana was common in parts of this prairie. ridge shown in fig. 14. Andropogon sco- parius was the dominant grass; A. gerardi and Bouteloua curtipendula were present. The prairie and a part of the adjacent woodland on the slope to the northeast were burned during the autumn of 1950 by a fire that swept the blufis from Rock- port northward to a point beyond this prairie. Clendenny.—When last seen, this hill prairie, located in the northwest quarter of section 12, T. 8 S., R. 4 W., about 2.3 miles north of Belleview, Calhoun Coun- ty, covered about 7 acres of the upper- most southwest-facing slope of a bluf¥. This bluff, fig. 15, served as the pasture of the Clendenny farm. Prairie covered the rocky slope above the rock ledge ex- cept in a few coves where a mixed forest extended upslope. Loess capped the bluff. Prairie covered the spurs and most of the coves; small trees and shrubs grew in scattered clumps in some coves. On the ported both forest and prairie: mixed for- est on the northwest part and a mixture of prairie and forest on the southeast part. Clendennv prairie was visited April 15, May 27, and September 8, 1950; Au- gust 30 and September 27, 1951. Swarnes.—An inscription on the mon- ument* at the crest of the blufif in the northeast quarter of section 35, T. 9 S., R. 3 W., at the north limits of Hamburg, Calhoun County, furnished the name for this hill prairie. When the site was last seen, prairie occupied about 2 acres of the west- and southwest-facing slope of the ridge. A fence located a few feet north *The following inscription appears on this monument: In Memory of Capt. Lewis Swarnes Born Mav 23. 1821 Died July 11, 1867. Lewis Swarnes, according to several residents of Ham- burg, was a riverboat captain. He became ill on one of his trips and requested that his body should be buried on the blufT overlooking the Mississippi River at Ham- burg. August, 1955 EvERS: Hill Prairies of Ii.i.ixoi 401 Fig. 16.—Part of the west-facing slope of Swarnes hill prairie at Hamburg, Calhoun County. Echinacea, Melilotus, and Psoralea were common on this slope. of the monument divided the prairie al- most equally into pastured and unpas- tured areas. The pastured segment occu- pied a west-facing slope, fig. 16, the un- pastured a west- and southwest-facing slope. The unpastured surface that bor- dered the rock ledge was stony, level near the ledge, and gradually steepening up- ward from the ledge. Bouteloua curti- pendula was there locally dominant. In- terspaces contained many individuals of Hoiistcjtiia nigricans. The unpastured prairie of the steeper slopes and the top of the loess-capped bluff were dominated by Atjdropogon scoparius. Scattered clumps of Bouteloua curtipendula and A. gerardi were present, and Asclepias steno- phylla occurred occasionally in the inter- spaces. The pastured slope supported a prairie that was dominated by A. sco- parius. Near the top of the bluff, as well as at the top, Rhus glabra was locally dominant. Psoralea teuuiflora was com- mon in the pastured prairie area. Swarnes prairie was visited September 7, 1949; April 14, Mav 27, Julv 1, and August 12, 1950; and September 27, 1951. Along Rock, Sangamon, and Illinois Rivers Devil's Backbone.—The bluff-ridgc that extends along the Rock River in the northeast quarter of section 16, T. 23 N., R. 10 E., south of Oregon, Ogle County, is given the name Devil's Backbone on the Dixon quadrangle of the United States Geological Survey topographic map. St. Peter sandstone underlies this ridge. When the ridge was last seen, one south- east- and two northeast-facing prairie openings occupied the upper stony and sandy slopes. Sandstone fragments were abundant on the northeast-facing slope. The openings on this slope were covered with prairie in which Poa pratensis was very abundant, Andropogon scoparius less abundant, and Bouteloua curtipen- dula scattered throughout. Syiithyris bul- lii also grew there. The southeast-facing opening was a sand prairie on a slope. A . scoparius was there the dominant grass. Selaginella rupestris. together with mosses and Audrosace occidentalis, grew in the interspaces. Devil's Backbone was visited 402 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 on June 23 and October 3. 1950, and May 7. 1951. Standard.— In 1951, prairie occupied about a balf acre of the upper southwest- facing ravine slope in section 26, T. 33 N., R. 1 W., 1 mile west and 3 miles north of Standard, Purnam County. Pet- alostemum piirpureum, Amorpha can- esrens. and Conopsis pahnata were some of the plants in this prairie. This site was visited July 7. 1951. Magnolia.—When the prairie opening given this name was last visited, it occu- pied slightly less than an acre on the west- to south-facing upper slope of the bluff in the southwest quarter of section 34, T. 31 N., R. 2 W., about 7 miles west of Magnolia, Putnam County. The bluff is capped with till ; loess, if present, apparently is very thin. Scattered shrubs of Rhus glabra occurred throughout the opening. Cornus drummondi and small elms grew on the south-facing slope, where also a few dead and scattered stems of honey locust were seen. Jfidro- pogon scoparius was the dominant grass. Comandra umbellata was very abundant, Psoralen tenuiflora common. Mixed for- est surrounded this prairie opening. Mag- nolia prairie was visited on September 29, 1949; May 16 and August 4, 1950. East Henry.—This name designates a group of five prairie openings on the southwest-facing bluff of Sandy Creek ; the bluff is in the northwest quarter of section 3, T. 30 N., R. 2 W., and south- east of Henry, Marshall County. When the area was visited August 4, 1950, the westernmost opening was weedy and much disturbed. At the base of the b'uff below this opening was a gravel pit. The next opening eastward supported prairie plants and also a thicket of Rhus glabra, Cornus drumtnondi, Malus ioensis, and Ulmus sp. This opening and the next one to the east were pastured. In the prairie areas, Andropogon scoparius was the dominant grass, Bouteloua curtipendula, Psoralen tenuiflorn, and Silphium Incinin- tum were common. Weeds, Chamaesyce maculata, Aiedicago lupu'inn, Poi/isettia detitata, and Melilotus alba, were fre- quently encountered in these areas. Prai- rie openings on the two easternmost spurs were not examined. Reavis Spring.—This prairie, when visited, covered almost 19 acres of the sandv loess bluffs in parts of sections 25, 26, and 36, T. 20 N., R. 7 W., about 5 miles south of Easton, Mason County. The name Reavis Spring was that of a school house, abandoned and later re- moved, that once occupied a part of the lower slope of the bluff in section 26. A road, which followed the general south- west-facing bluff, was on the lower sandy slopes. Downslope to the southwest was a series of thickets and cultivated fields. Upslope to the northeast was the prairie, which occupied numerous spurs. Thicket covered the bases of some coves, shrubs or prairie the upper slopes. Prairie covered the crests of the spurs; mixed forest or prairie occupied the tops of the bluffs. The bluffs at Reavis Spring prairie rise 256 feet above the Sangamon River bot- tomland and are higher than the dissected upland to the northeast. The valley over- looked by these bluffs is notable in sev- eral respects. It has a wide bottom trend- ing generally east-west. The Sangamon River enters it from the south and joins a small, west-flowing stream, Salt Creek, in section 6, T. 19 N., R. 6 W., about 1 mile upstream from the Reavis Spring lo- cation. The valley is about as wide, rather surprisingly, above the junction of the Sangamon River with the small stream as below it. Salt Creek has a volume too small to account for so wide a valley. It is probable that through this valley a gla- cial torrent once drained a part of the Wisconsin ice-front, then some miles east of the Reavis Spring site, and brought down huge amounts of sand and silt. From these were derived the thick de- posits of loess and fine sand on the bor- dering bluffs. Other sizable hill prairies occur or did occur on the bluffs for a few miles east of the junction of Salt Creek with the Sangamon River. Reavis Spring prairie was visited Sep- tember 15, 1949; July 6, 1950; May 18, 1951 ; and March 25, 1952. The domi- nant grass was Andropogon scoparius. Also growing in the prairie were Agoseris cuspidata, Polytaenia nuttallii, and the easily overlooked Spiranthes cernun. The prairie, which served as a cow pasture, contained a number of weeds, Verbascum August, 1955 EvERs: Hill Prairies of Illinois 403 thapsus, Achillea millefolium, and Setaria viridis. On the last visit it was found that the prairie had been burned a week before, fig. 17. From the tenant farmer it was learned that this prairie is burned in early spring each year to allow an ear- Mud Creek.—In the years of this study, prairie occupied much of the sandy loess ridge that separates the bottomland of the Illinois River from Mud Creek in the northeast quarter of section 1, T. 16 N., R. 11 W., Morgan County. A thicket Fig. 17.—Surface of Reavis Spring hill prairie after an early spring fire. The size of the clumps of Andropogon scoparius is evident by comparison with the 1-foot rule. Her and more tender growth of grass than would normally occur. Bluff Springs.—Disturbed prairie, which covered about a half acre on the north part of a loess mound in the south- west quarter of section 21, T. 18 N., R. 11 W., 0.1 mile north of Bluff Springs, Cass Countv, was visited September 15, 1949; July 6, 1950; and May 18, 1951. The mound and the adjacent lower slopes were pastured. The lower slope on the west was occupied by a mesophytic dis- turbed prairie with Poa pratensis locally dominant. The steeper slopes of the mound were prairie, with Andropogon scoparius the dominant grass. Bouteloua curtipendula and several plants of Spiran- thes cernua occurred on these slopes. The almost level top, which had been much disturbed by trampling, supported a mix- ture of prairie and weeds. bordered the road on the lower north- west-facing slope. This thicket extended into the coves and partly up the cove slopes. Prairie covered the spurs and ridge-top, fig. 18. The dominant grass was Andropogon scoparius. Bouteloua curtipendula and B. hirsuta grew in scat- tered clumps in the prairie, Psoralea ten- uiflora was common, and Sisyrinchium campestre very abundant. All of this prai- rie and that part of the ridge that was covered with thicket, about 13 acres in area, served as a cow pasture. Visits were made to Mud Creek prairie on July 6, 1950; May 18, 1951; and March' 25, 1952. Northeast Meredosia.—When last seen, this prairie covered about 9 acres of the loess bluffs in section 9, T. 16 N., R. 12 W., about 6 miles northeast of Mere- dosia, Morgan County. Andropogon sec- 404 Illinois Natural History Survey Bulletin Vol. 26. Art. 5 t>arius was the dominant jjrass. Bouteloua lurtipendula, as well as B. hirsuta, was scattered throughout. Polyyala incarnnta grew on the hluft top. and Arteniis'ta cau- data grew as scattered individuals in the sandy loess. This prairie, which served as pastureland, was visited September 15. Psoralen teiiuiflora, Onosmodiuui occi- deiilale, and Ambrosia coronopifolia. Walnut Creek.—The site of this 2- acre prairie occupies one southwest- and two west-facing spurs of the bluff north of which W^ilnut Creek enters the Illi- nois River valley in the northwest quar- Fig. 18.—Spurs of Mud Creek hill prairie (center of picture) in northwest Morgan County. In the distance beyond the Mud Creek prairie are slopes, some of which support prairie. 1949; Julv 6, 1950; Mav 18. 1951; and March 25, 1952. Northeast Meredosia was the first of those hill prairies along the Illinois River observed by A. G. Vestal, who visited it in the spring of 1931 in company with James M. Schopf and Herman B. Wascher. They were impressed by the persistence of native prairie vegetation and by the lack of serious erosion on the steep loess slopes, over which the continu- ous trampling of cattle had worn steplike cowpaths. BluflFs.—When this site was visited July 6, 1950, a mixture of prairie and for- est covered about 8 acres of the west- facing slope of the bluff in the southwest quarter of section 10, T. 15 N., R. 13 W., north of Bluffs, Scott County. Prai- rie species included Lespedeza capitata, ter of section 26, T. 14 N., R. 13 W., about 4 miles west of Winchester, Scott Countv. When visited August 13, 1950, and April 24 and May 18, 1951, the base of the slope contained a mixture of prairie and shrubbery. The spur slopes contained prairie, with Andropogon scoparius the dominant grass. The coves between the spurs supported prairie and some woody plants. The top of the ridge was very weedy. Walnut Creek prairie was used as a horse pasture. North Eldred.—Located in section 16, T. 10 N., R. 13 W., 2 miles north of Eldred, Greene County, this prairie in 1949 and 1950 covered several spurs on the upper slope of the bluff. The spur di- rectly above the cemetery at the base of the bluff was heavily pastured ; the spurs to the south of this were also pastured but August, 1955 EvERS: Hill Prairies of Illinois 405 not so greatly disturbed. Stones strewed the slope in places just above the rock ledge ; sandy loess and sand capped the bluff. This prairie was visited Septem- ber 1, 1949; April 14, Mav 23, and Julv 25, 1950. South Eldred.— In 1950, prairie cov- ered about 4.5 acres of two southwest- facing slopes in the southwest quarter of section 4, T. 9 X., R. 13 W., 2 miles south of Eldred, Greene County. The prairie formed an inverted U with the prongs of the U extending downslope. A ndropogon scoparius was the dominant grass; Senecio plattensis and Lithosper- rnum cnnesrens were common. This site was visited May 23, 1950. Richwood.—When last visited, this prairie, in the southeast quarter of section 8, T. 8 N., R. 13 W., Richwood Town- ship, Jersey County, occupied 4 acres of the long, curved ridge which extends from the rock ledge on the southwest up to the bluft-top. The abundant grasses were Andropogon scoparius. A. gerardi, and Bouteloua curtipenduln. A small arm of the prairie stretched northwestward on a small branch of the ridge. A mixed for- est covered the bluff slope to the west and the ravines on the east and north. Rich- wood was visited September 7, 1949, and May 23, 1950. Pere Marquette.—At the time of this study, prairie vegetation occupied about 3.5 acres on the spurs o.' the southwest- facing bluffs, Pere Marquette State Park, west of Grafton, Jersey County. The prairie observed for this study was on the slopes west of the westernmost parking area that was located on the crest of the bluff. Mixed forest grew in the coves between the grass-covered spurs. A little below the top of the eastern and central spurs a firebreak crossed the prairie. ^Veeds, including Ambrosia elatior and Erigeron canadensis, grew among scat- tered plants of prairie species in this fire- break. The dominant grass of the prairie slope was Andropogon scoparius. Dcs- nianthus illiiioensis grew on the western spur and was very abundant on the cen- tral one. The western spur was disturbed by a bridle path which followed the crest of the spur and had cut 2 feet into the loess. The bluff-top was covered by a thicket of small trees and shrubs, includ- ing Crataegus crus-galli, Cornus drum- niondi, Malus ioensis, Cercis canadensis, and Sassafras albidum. Pere Marquette was visited July 8 and August 29, 1950; May 25 and November 29, 1 95 1. Grafton to Cairo and Elsewhere in Southern Illinois Chautauqua.—A small village resort at the convergence of several ravines about 3 miles east of Grafton furnished the name for this prairie. The prairie, a part of section 13, T. 6 N., R. 12 W., in Jer- sey County, covered four south-facing spurs, mixed forest the coves. The base of each spur was a rock ledge at the top of the cliff' which here closely parallels the Mississippi River. The spur slope above each ledge was covered with prai- rie; Andropogon scoparius was the dom- inant grass. Melica nitens occurred on the stony prairie slope above the ledge. Numerous weedy species such as Setaria viridis, Achillea niillefoliuni. Ambrosia elatior, Lappula echinata, and Geranium carolinianuni were present. Chautauqua hill prairie was visited Tulv 8 and August 29, 1950; also May 25, 1951. Principia.—A college furnished the name for this hill prairie, a part of the college campus. At this location in section 20, T. 6 N., R. II W., east of Elsah, Jersey County, the bluff of the Mississippi River has a high limestone cliff' that is capped by a mantle of loess. The cliff is not a simple wall, but has sharp salients projecting well beyond the loess spurs above them, fig. 19. Prairie, with an area of 4 acres, predominated on the spurs in 1950 and 1951. Andropogon scoparius was the dominant grass ; Sporobolus asper was locally abundant. Several paths used by students traversed the spurs and the crest of the ridge; elsewhere the prairie was undisturbed. The lower parts of coves supported mixed forest. Above this forest, tree seedlings and Rhus glabra occurred scatteringly to the top of the ridge, fig. 20. The north side of the ridge was well forested. Principia prairie was visited April 21, May 23, July 8, and August 29, 1950; Tulv 5 and November 29, I95I. 406 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 Fig. 19.—Part of the cliff at Principia, near Elsah, Jersey County, with sharp rock salients that project beyond the spur fronts above. Fig. 20.—An upper slope of a cove of Principia hill prairie with a mixture of prairie plants, Rhus glabra, and small oaks. August, 1955 EvERs: Hill Prairies of Illinois 407 Oblate Fathers.—This name, taken from the mailbox at the entrance to the property on which the prairie is located, was adopted to designate a much-disturbed hill prairie situated in the northeast quar- ter of section 5, T. 5 N., R. 10 W., be- tween Alton and Clifton Terrace, Madi- ridge between Illinois highway 157 and the CoUinsville road just north of Casey- ville in St. Clair County was the site of this hill prairie. The name of this prairie was derived from the presence of aban- doned concrete bunkers along the high- way. The site was visited July 8 and Fig. 21.—Block House hill prairie, near Gltn Carbon, Madison C ouiit\. I;. is a cultivated field, beyond which are prairie spurs. reground son County. When this site was visited on July 25, 1951, prairie with many weeds covered about 3 acres of the south- west-facing bluff slope that served as a pasture for horses. Block House.—Responsible for the name of this hill prairie was the shape of a small house on the bluff-top in the northeast quarter of section 32, T. 4 N., R. 8 W., west and north of Glen Carbon, Madison County, fig. 21. Block House was visited July 8 and August 29, 1950; also May 24, 1951. Here the bluff was seen to be deep loess, with no visible rock outcrops. The lower slope of the bluff bordering the highway was a cultivated field ; the upper slope had prairie-covered spurs and thicket-covered coves. Atidro- pogon scoparius was the dominant grass. The top of the bluff was a disturbed prairie. Bunker.—A group of loess mounds in section 5, T. 2 N., R. 8 W., that form a August 29, 1950; also May 24, 1951. The east-facing slope of the ridge sup- ported a mixed forest. On the west-fac- ing slope of the ridge were prairie spurs, much disturbed by mules and cattle that grazed this land. The steep spur-fronts were prairie, the coves more or less wooded. One small cove contained much prairie vegetation, including Silphium in- tefffifolium, Vernonia missurica, and Cacalia atripUc'tfolia. A thicket covered the base of the slope. Edgemont.—This hill prairie, located in the southeast quarter of section 26, T. 2 N., R. 9 W., in Edgemont, a subdivision of East St. Louis, in 1940 occupied 4 acres of the bluff slope as determined by planimeter from aerial photographs. An- dropogon scoparius, A. gerardi, and Bou- telnua curtipendula were some of the prai- rie grasses on this slope when the prairie was visited on September 2, 1949. This prairie, because of its location, is rapidly 408 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 Fig. 22.—Valmeyer hill prairie, 3 miles south of Valmeyer, Monroe County. being destroyed and replaced by homes was found with other prairie plants on and lawns. " this bluff. ^ ^, . . ... Southwest Edgemont.—A very small Sugar Loaf.—This name is on the La- hill prairie occupied a part of the bluff in hokia sheet of the topographic map for section 4, T. 1 N.. R. 9 W., southwest that part of the bluff 1 mile south of of Edgemont, when this area was visited Dupo, St. Clair County, that was visited September 2, 1949. Audropogon scoparius July 9, 1950. Prairie, with Bouteloua Fig. 23.—Part of the eroded cliff at Valmeyer hill prairie; prairie visible at upper right. August, 1955 EvERs: Hill Prairies of Illinois 409 curtipendtila locally abundant, covered both the rocky lower slope and the loess which capped the bluff. The loess had been badly disturbed by earth-moving op- erations to provide level homesites. Valmeyer.—When visited, this hill prairie occupied the southwest-facing was visited. An open mixture of trees and shrubs, with much Juniperus virginiana, surrounded the prairie openings, fig. 24, South along the bluffs large spurs were completely covered by prairie. The entire loess slope, with no visible rock outcrops, served as pastureland. This site was vis- Fig. 24.—Prairie openings at Chalfin Bridge, Monroe County. Prairie is visible on the parallel ridges between rows of red cedars which grow in the coves. slope of the ridge north of Monroe City Hollow about 3 miles south of Valmeyer, Monroe County, fig. 22. The site was visited September 2, 1949; April 22, Mav 24, July 9, and August 30, 1950. Prairie covered almost 9 acres of the upper slope between the cliff and the crest of the bluff. Above the eroded cliff, fig. 23, the slope was stony ; the upper part was loess. The east-facing slope at the highest part of the ridge supported a mixed forest ; far- ther south along the ridge, prairie covered the upper east-facing slope and a mixed forest occupied the basal part of the slope ; at the southernmost part of the ridge only mixed forest occurred. In some places the rock outcrops were merely small vertical drops separated by steep rocky slopes on which much Juniperus virgini- ana grew. In the prairie above the rocky slopes, Andropogon scoparius was the dominant grass; Psoralen tenuiflora was common. Ghalfin Bridge.—Prairie openings oc- cupied the bluffs southeast of Chalfin Bridge, Monroe County, when this area ited August 30, 1950, and visited and photographed February 6, 1952. Fults.—This hill prairie located on the bluff south of Fults Creek, southeast of the village of Fults in Monroe County, was visited September 11, 1948; June 16 and August 30, 1950; also May 24, 1951. It occupied about 12 acres, extended 0.6 mile along the upper southwest-facing slope of the bluff-ridge, fig. 25. On the northwest part of the bluff-ridge, long prairie spurs descended from the bluff-top to a small rock outcrop with a vertical face 2 to 3 feet high, below which was a forest-covered rocky slope that formed the lower third of the bluff. The coves be- tween the long prairie spurs supported a mixed woodland. On the southeast part there was a high limestone cliff, and above it prairie covered both spurs and coves, which were there very poorly defined. Galium virgatum and Heliotropium te- nellum, rare in Illinois, grew on the lime- stone ledge. Renault.—Located about 2 miles south of Renault, Monroe County, this prairie 410 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 when last visited extended about 0.7 mile along the bluft-ridge and occupied almost 14 acres, of which 5 were studied. There was very little level area just above the rock ledge ; the steep loess slope abruptly ended at the cliff. Andropogon cupied the coves. Juniperus virginiana, Querciis muhlenbergii, and Carya texana grew on the narrow bluff-top ridge. The east-facing slope of the ridge was a fairly productive pasture, presumably once wooded. The prairie spurs were grazed. Fig. 25.—Fults hill prairie, southeast of Fults, Monroe County. scoparius was the dominant grass. Re- nault was visited Julv 30, 1950, and Mav 24, 1951. Phegley.—The appellation for this prairie came from the name of the former tenant and caretaker, W. H. Phegley. In 1950 and 1951, the prairie occupied 6.33 acres of the southwest-facing slope of the bluft-ridge above the Columbia (Solvay) Quarry, 1.1 miles north of Prairie du Rocher, Randolph County, The lower part of the brow slope above the limestone ledge at the top of the 200- foot cliff, fig. 26, was covered with frag- ments of limestone. Prairie occupied this almost level stony surface, which meas- ured about 10 to 15 feet in width. Loess covered the bluff above this surface. This mantle of loess was dissected to form a series of spurs and coves, fig. 27. The spur fronts were steep, the upper slopes gently sloping upward from the fronts to the top of the bluff. Prairie, with Andropogon scoparius as the dominant grass, covered the spurs ; prairie, forest, or a mixture of both oc- though apparently less closely than the main part of the pasture. The principal results of grazing on the prairie spurs were the thinning of the native cover and the introduction of a few weeds. Plots were staked on this and the adja- cent prairie toward the northwest to fur- nish data for vegetation studies of this report. Phegley hill prairie was visited June 15, Julv 29, and September 19, 1950; May 23, September 18, October 9-10, and October 16-18, 1951. Sampson.—The name applied to this prairie was that of the farmer on whose land the prairie occurred. Sampson hill prairie, 4.5 acres in area, was actually a continuation of the Phegley hill prairie, from which it was separated by two par- allel wire fences, 3 feet apart, an effec- tive barrier against grazing cattle. The Phegley prairie served as a pasture; the Sampson prairie was not grazed. Located to the north of Columbia Quarry, the Sampson prairie was similar in most fea- tures to the Phegley prairie. However, August, 1955 EvERS: Hill Prairies of Illinois 411 Fig. 26.—The cliff at the Columbia (Solvay) Quarry, north of Prairie du Rocher. The Phegley hill prairie occupies the slopes above this cliff. The spurs and coves shown in fig. 27 are located above the cliff near the right edge of the picture. Sampson prairie is to the north (left) of Phegley prairie. Fig. 27.—A part of the Phegley hill prairie north of Prairie du Rocher. A small cove is visible in extreme lower left corner, a larger one near center of picture between two large spurs, which are plainly visible. 412 Illinois Natural History Survkv Bulletin Vol. 26, Art. 5 the bluft'-top ridtje and the east-taciiiy; slope of this ridjie were forested, except for some cleared areas servinji as fields for cultivated crops. This prairie was visited on the same dates as Phejjley. Stotz.—This hill prairie took its name from a quarry about a half mile north of Prairie du Rocher. Eijjht spurs of a bluft- ridjje comprised the prairie, which covered about 6 acres in 1^50; intervening ravines were wooded. The southernmost spur had been much trampled b\ humans, the others pastured. Native plants and weeds occurred on the pastured spurs in nearly equal proportions; the native plants per- sisted better on the nonpastured spur than en the others. Andropoyon scoparius was the dominant grass of the prairie slopes. Patches of Bouteloun curtipendiila grew throughout the prairie. The orchid Htx- (ilfctris spicato was found in the wood- land border at the base of one spur. Stotz prairie was visited May 24 and July 30, 1950. Allen Lake.—A small, crescent-shaped lake located near a loess-capped bluff-top supplied the name for this prairie, which was visited July 2^, 1^50. The prairie was west of the lake and 1.2 miles south of Prairie du Rocher. Prairie occupied 4.5 acres of the upper slope of the bluff. Limestone fragments covered the lower part of the slope. The dominant grass was A lulropogon scoparius. South Prairie du Rocher.—When visited June 16, 1950, this very small, pastured hill prairie occupied a part of the bluff 1.6 miles south of Prairie du Rocher. Andropogon scoparius was the dominant grass. Cacalia tubcrosa was found growing in the loess. Grand Canyon.— In 1949, this small prairie opening in section 2, T. 10 S., R. 3 W., 8 miles southwest of Murphysboro, Jackson County, occupied a west-facing slope at the north end of the bluff called Chalk Bluf¥, just south of the mouth of the valley known a> Grand Canyon. An- dropogoti scoparius was the dominant grass. Small trees of hickory, sassafras, and white oak were scattered throughout. Grand Canyon prairie was visited Octo- ber 28, 1949. Fountain BlufF.—This hill prairie, observed in 1950 and 1951, took its name from the isolated upland known as Foun- tain Bluff, which has a dissected loess top and for the greatest part vertical sand- stone walls and is situated between the Mississippi River and the broad bottoms of the Big Muddy River west of the main chain of bluffs in western Jackson County. This isolated upland extends 4 miles north and south, and is 1.8 miles across at the widest part. Prairie-covered slopes were observed in section 36, T. 9 S., R. 4 \y., at the northern end of Fountain Bluff, a distance of about 1 mile west and a little south of Gorham. The northern and northwestern side of Fountain Bluff is an almost vertical sandstone wall into which a sizable ra- vine has cut southeast and then eastward so that part of the ravine is almost paral- lel to the !-teep northwest wall. A sizable ridge lies between the ravine and the Mis- sissippi River bottomland on the north. On this ridge were the prairie-covered slopes, described in detail below. Above the vertical rock cliff which forms the northeast wall of the ravine are four rock-strewn spurs, which at the time of this study were covered with prai- rie plants; Andropogon scoparius was the dominant grass. These prairie-covered spurs were separated by three narrow belts of woodland in shallow drainage- ways. The three narrow belts of wood- land were joined upslope to form another and larger belt of woodland, at right an- gles to the three ; the larger belt covered a rock-strewn slope. a Upslope from the rock-strewn slope, the bluff is capped by loess. Three spurs on this highest exposure of the ridge were occupied by prairie, the intervening coves by small trees and shrubs. One spur faced almost westward, overlooking the Missis- sippi bottomland, the others southwest- ward. The westward-facing spur was separated from the others by a narrow S belt of timber. At the ridge-top, the prai- ' rie areas of the two southwest-facing spurs were connected to form a U-shaped hill prairie with the prongs of the U ex- tending downslope. When visited June 14, August 17, and September 19, 1950, and April 19 and May 23, 1951, prairie occupied about 3 acres of these spurs. August, 1955 EvERs: Hill Prairies of Illinois 413 Government Rock.—Located in the southeast quarter of section 9, T. 11 S., R. 3 W., 4.5 miles north of the village of Wolf Lake, Union County, this hill prai- rie, when visited, occupied one of the siz- able spurs which extends from the sum- mit downslope to the rock cliff in that portion of the Mississippi bluffs known as Pine Hills. The appellation here used — Government Rock—is the one applied to this spur on the Wolf Lake sheet of the topographic map. Above the cliff at the base of the spur is a steep west- and southwest-facing slope strewn with chert stones. When last seen, the lower part of the slope was oc- cupied by a thin stand of undersized trees. Above this was prairie, dominated by Andropotjon scoparius and Boutelotia curtipendiila. A few small trees of Quer- cus muhlenbergii, Ostrya virginiana, Ju- niperus virginiana, and Virburnum rufidu- tum occurred in several open groups within the prairie. Upslope on the spur was a strip, about 20 feet wide, with fewer prairie plants and an abundance of Tephros'ta virgini- ana. This strip was followed by a zone of mixed upland forest, which included Quercus muhlenbergii, Q. stellata. Sassa- fras albidum, Juglans nigra, Carya spp., Cercis canadensis, and some large trees as well as seedlings of Finns echinata. Vacciniutn arboreiun and Ceanothus americanus were common shrubs. The uppermost part of the spur, which was capped by loess, was occupied by prai- rie vegetation. The narrow ridge-top had been much disturbed by picnickers. The east-facing slope of the bluff-ridge was forested nearly to the ridge-top. Government Rock was visited October 27, 1949; August 17 and October 16, 1950; April 19 and May 23, 1951. Tamms.—This hill-top prairie open- ing, about a half acre in area and located on the crest of a cherty ridge in the south- east quarter of section 35, T. 14 S., R. 2 W., 1 mile west and 1 mile north of Tamms, Alexander County, was visited September 20, 1950. The prairie area, containing such plants as A ndropogon gerardi, Solidago nenioralis, and Helian- thus divaricatus, was surrounded by a woodland of xeric oaks, hickory, and some sassafras. One of the oaks on this ridge was Quercus montana. Cave Creek.—When this area was last visited, a rock (limestone) hill prai- rie occupied part of the bluff on the east side of the confluence plain of Dutchman and Cave creeks, somewhat over a mile east of the Cache River, in the northeast quarter of section 28, T. 13 S., R. 3 E., about 5 miles south of Vienna and 1.5 miles northeast of Forman, Johnson County. The base of the bluff was wooded, but it had been much disturbed during the construction of a power line. The prairie opening above the disturbed wooded bluff base occupied about 1.5 acres of the south- and southwest-facing slope of the ridge. The prairie slope was strewn with rock fragments which had eroded from outcrops at various levels on the slope. In some places the slope was almost a rock pavement. Grasses and composites were the predominant vege- tation; a few small trees of Quercus muhlenbergii, Juniperus virginiana, Cor- nus florida, and Crataegus spp. were found scattered throughout. The trees did not reach full size ; after they had at- tained heights of 10 to 15 feet the tops lost vigor and the trees died. Upslope from the prairie, the broadly rounded ridge was forested, but it had openings occupied chiefly by Andropogon gerardi. An interrupted limestone ledge traversed this forested surface. Much Nothoscordum bivalve grew in the crev- ices of this ledge. Cave Creek prairie was visited June 10, August 17, and September 20, 1950; April 18 and May 22, 1951. FLORA OF THE HILL PRAIRIES As a means of determining what spe- cies of plants occur in Illinois hill prai- ries, numerous collections were made from early September, 1949, to the middle of October, 1951. Many of the plant spe- cies very common in Illinois were col- lected from only one prairie but their oc- currence in other prairies was recorded in the field notes. Species less common were collected from each prairie site in which they were growing. More than 414 Illinois Natural History Survky Bulletin Vol. 26, Art. 5 3,000 specimens were collected from the prairie areas; numerous others from the adjacent rock ledges, upland woods, wooded coves, and basal slopes of the bluli's. These specimens now form a part of the collections in the herbarium of the Illinois Natural History Survey at Ur- bana. Collections and identification of hill prairie plants added several species to the known Illinois flora. Rudbeckia T/iissouri- ensis was one of the rare plants reported (Evers 1951). The collections verified the present-day existence of certain spe- cies reported over a half century ago from Illinois but not collected in the state again until the field work for this study was undertaken. Menizelia oUgosperma is a notable example. The collections also in- creased the knowledge of the distribution of plants having somewhat restricted ranges in Illinois. Thus, it is now known that Bouteloua curtipendula ranges al- most continuously, in suitable habitats, from northern to southern Illinois along the western border, that Psoralen tenui- flora ranges southward into Monroe County, and that Houstonia nigricans is quite common on loess slopes in south- western Illinois. The hill prairies contain prairie, wood- land, cultivated, and introduced species. The woodland species are occasionally found in prairie just as the prairie spe- cies are found in woodland, especially in adjoining border areas. The cultivated plants usually are escapes that have be- come established in the hill prairies. Some, Lespedeza stipulacea for example, had been planted in certain prairies or in ad- joining pastures by the landowners. Asia and Europe are the original homes of 30 of the species found. North America of the remainder. Annotated List of Species This list was compiled from collections made and notes taken on the Illinois hill prairies visited. Field notes were used to supplement the distribution record but no species is included in this list unless it was collected from at least one prairie. The list is not intended as a complete flora of the Illinois hill prairies. Such a compilation would require much addi- tional time and many additional visits to these sites. In some cases, only the gen- eric name of a plant is given. Thus, the four species of grapes are included in this list under the term Vitis spp. In most in- stances, both generic and specific epithets are used. Any pertinent synonym is placed within brackets following the sci- entific name. Brief notes on the occur- rence of each plant or plant group follow its name. The name of each plant that is of foreign origin is preceded bv an aster- isk (*). Table 14, which summarizes presence, as discussed on page 392, contains a partial enumeration of the annotated list of spe- cies. Species found only on rock ledges, in coves, or in woodland borders near, but not in, the prairie stands of any site listed in table 14 are not indicated for that site. Some species mentioned in the annotated list are not included in table 14 because they are not native to North America or are not regarded as characteristic prairie species. Lecideaceae Lecidea spp. Lichens of this genus were found in 14 hill prairies. Two sam- ples were identified by Dr. C. W. Dodge of the Missouri Botanical Garden as L. decipiens and L. demissa. These plants grew between grass tufts under the shade of the grass foliage on either loess or fine rock fragments. MarchANTiACEAE RebouUa hemisphaerica (L.) Raddi. This was a frequently encountered liver- wort on loess and rocks of hill prairies, where it grew in interspaces between bunches of grass. Musci An unidentified moss (or mosses) grew on loess of some hill prairies. All plants examined lacked sporophytes and accord- ingly remain unidentified. Selaginellaceae Selaginella rupestris (L.) Spring. The rock selaginella grew in the sandy hill prairie at Devil's Backbone. Although found on sandstone outcrops in southern August, 1955 EvERs: Hill Prairies of Illinois 415 Illinois (Pope County), apparently it is absent from similar situations in the Fountain Bluff hill prairie. Equisetaceae Equisetutn hyemale L. The tall scour- ing-rush was seen in three hill prairies, Rock Island 31, Bunker, and Southwest Edgemont, where it occurred in loess. It was not seen on rocky slopes. Equisetum laevigatum A. Br. [£. kan- sanum Schaffn.] The smooth scouring- rush was observed in seven bluff prairies, all of them in northern or central Illi- nois. POLYPODIACEAE Cheilanthes lanosa (Michx.) D. C. Eaton. The woolly lip-fern was found in rock prairie at Cave Creek. It was more abundant, however, on rock outcrops than on prairie slopes. Pellaea atropurpurea (L. ) Link. Al- though the usual habitat for purple cliff- brake is calcareous rocks, it occurred on the loose stony slopes at Cave Creek and Government Rock. PiNACEAE Juniperus virginiana L. Red cedar was found in both rock and loess hill prairies and was common on rock ledges at the bases of prairie slopes and in wooded coves. It was the only tree species on some of the prairie slopes. Steyermark (1940) noted its frequent occurrence in Missouri glades. Gramineae Agrostis hiemalis (Walt.) B.S.P. Ticklegrass was encountered only in rock prairie at Fountain Bluff. Andropogon gerardi Vitman. \^A . fur- catus Muhl.] The big bluestem is an abundant prairie grass in Illinois. It was observed in 37 hill prairies. It was found as a dominant only in scattered patches, and in this status in only a few hill prai- ries. Andropogon scoparius Michx. Little bluestem was found to be the usual dom- inant and is the most important grass of the hill prairies of Illinois. Andropogon virginicus L. Broomsedge, a common grass in open woods, old fields, and along roadsides in southern Illinois, was not found to be an important species of the hill prairies, having been seen in but one, Fountain Bluff, on the loess prai- rie slopes. Aristida basiramea Engelm. ex Vasey. This plant was collected in only the Sun- set Trail hill prairie. Aristida intermedia Scribn. & Ball. This was observed only at Hill-Top and in the sandy prairie at Devil's Backbone. Aristida longespica Poir. This three- awned grass was collected in prairie at Devil's Backbone and from a rock ledge at Cave Creek. Aristida oligantha Michx. This weedy species was collected in only the Seehorn- Payson hill prairie. Bouteloua curtipendiila (Michx.) Torr. Side-oats grama was found in 48 of the hill prairies examined. In southern Illinois, it was found in Cave Creek and Government Rock prairies, but it was not observed at Tamms, Fountain Bluff, or Grand Canyon. It was seen at most of the sites examined from Allen Lake northward along the Mississippi and Illi- nois rivers. Vestal (1945) mentioned "hill prairie and sandstone cliff-tops" as common habitats of this species in Illinois. He observed in July, 1941, that this Bou- teloua dominated several steep southwest slopes of prairies along the lower Illinois in Jersey County, sites not included in this study. Side-oats grama was the dom- inant grass just above the rock ledge at Swarnes; a few feet higher on the prairie slope, Andropogon scoparius was domi- nant. Bouteloua hirsuta Lag. Hairy grama was observed in eight hill prairies, most of them in northern Illinois. It grew in the heavily pastured loess prairie at Bald Bluff and also along the bluffs of the Illi- nois River at Mud Creek and Northeast Meredosia in central Illinois. *Bro?nus commutatus Schrad. Hairy chess was found in loess and rock prairie at five sites and in crevices of rock ledges at two others. *Bromus tectorum L. Downy chess or cheat was found in situations similar to those of hairy chess. It was more abun- dant in crevices of rock ledges than in hill prairie. 416 Ii.MNOis Natural History Survey Bulletin Vol. 26. Art. 5 ' c a.iS ! 0-5.S *' . « o -05°i U £ V C O ." *' « o 2:^« — °-®f " = "5 £ <« «j o> 'o « 2 «) c ^-5 S— " o a> (A (A Mi -a Ji o > 3 3 C '^w u "- OS uo ^— ^ o c « j= O C3 U. « — 4) ^ « <« > ^ J _ J^« = ^ 4J o £ _ E 3 - « « c :r ;= j= = . *^ ^ 4) w C3 -w^a - O" c c -2 ti o 2 c ""« 2 so 2 E oU " E 3 ;. 3 (A < tii Q. •5 P >« Q-' •01).- _2 '5 Oh « 2 ^ O- C Q. o 3 -o S « > 2 in in i"5l « 2 ! IS •«e > O "> I. a> _ OS .2 " « e •5 = 5 •• « a *5 H «2 « « M « = a..- ew u c T vxo L ^33^3 3AVD ^DO^ XN3WN^I3A0Q ajmg nivj-niioj zxoxs A3T03HJ NOSdWVg J.TnVN3^ sxT n^tj >I3A3WTV^ HHNNng 3snoH MOOTg VldlONI^J va?^nvxnvH3 axxanb^vjAj 3>iaj aa^aig Hx^O]y[ >133>I3 XIINIV^YX VISOa3>!3p\I XSV3HX^O;y[ •M3a^3 any^ SONI^dg jjmg ONI^dg siAva'y vnoNOvp\[ 3NOa513Vf{ S TIAafl SHN^VMS ANN3aN3T3 NOXNV3 M3;vJ Hxnog sNoissag — — LO — fN _00—> — — '— — I ++ ++ + + + ++ + + + + + + + + + + + + + + + + + + + + + NOSAVJ-N^OH33S 3-Mvq N3aaif| NVPMOf^ il33^3 >130^ VS>IQ VlAI313ia S3avsnvjj Hxnos TIV^JL X3SNnS NOIXVXg 33NIIA10Naj^ OHONV^ ig + + + + + + + w <. u (J <. p •2 w ^- « < i- w -«:'~2 o ++++ ++ ++ + ++ + + ++ + + ++ + ++ + + ++ + + ++ + ++ ++ + + ++ + + ++ + + + + ++ + ++ ++ + ++ + + ++ + ++ + ++ ++ + ++ + ++ ++ + + ++ + ++ + ++ + ++ + + ++ + ++ ++ + + ++ + + ++ + + ++ + + ++ +++ '~ t- '5! < -n R s R 5 ^o o o J- K O O C> .j^ >; R :~ ^j ~5: 5^ « « « -S So •c:5sC.c^^^^^o^55 . S S _ _ , , , - 5:-^ (ja, "^ "^ '^ '^ "^ "^ "^ "^ oq 03 ^ tq August, 1955 EvERS: HiLr. Prairies of Illinois 417 — — "-1 — rorl—'— ' — — — (^ItNr-) — — — u^O0C^-Or000CNr0fN\C oo — —i — — CNtNt-) 418 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 TVXOJL Tj. ^•4- * ^ -^ — I r-» VO oo ^33^3 3AV3 + + + NDO^ XN3WNH3AOJ) + + jjmg NivjuNOOji + + + ++ ziOJ-S + A3T03HJ + + + + + NOSdWVS + + + xinvNS^ + + + sj.Tnj + + + H3A3WTV^ + ++ >i3MNng + + 3snoj^ Nooig + + + VldlDNIHJ + vii75nvxnvH3 + + + + 3J.13nt)^VJ^ 3U3J a3^aig hx^o^ + + -H33'a3 XnNTV^ + VISOa3YI3p\[ XSVSHX^OJsJ + _+ +M331I3 aay^i + soNindg Jjmg + + ONI^dg siAva^ + + + vnoNOvj\[ + + 3Noa:40vg s^iia3q + + + saN'avMS + ANN3aN3T3 + + + + N0XNV3 Ava^^ Hxnos SNOISSHg + NOSAVJ-N^OHaag a-Mvq Nsaaifi + NVWOJ-J ^aa^3 :<3o^ + VS'HQ + VW313ig + + + ssavsnvj Hxnos + + TIV^JL XaSNAg + NOIXVXg 3aNIWON3p\[ + + + + + OHONVy 13 + + ^•S -< ^ J' o S S- < ii 5 < -J ^J <• -^ ** UJ ._ r;_s D '^ «-J ~ u « .^ »• ^. <^ *^ O ' H ? > 5 o s <; r" o ^ b; R R i; J « z -^ O S K C/3 03 Cj tt, ^ < s <3 <; (o Cjc^ August, 1955 EvERs: Hill Prairies of Illinois 419 (N ro -H 420 Illinois Natural History Survey Bulletin I Vol. 26, Art. 5 T vxo L ^33H3 3AV3 •MOOy XN3WN^3AOf) jjmg NiviNnoj zxoj,s A3T03HJ NOSdWVS j.nnvN3^ snn>j ^3A3WTV^ >i3^Nng 3snoH ^oong VldlDNI^fl vnbavxnvH3 3Xj.anbHvi\[ an3(f aa'aaig hx^o^ M33«3 XnNTV^\ VISOa3^3p\[ XSV3HXVO|sJ M33^3 aap\[ soNi^iag iimg ONI^dg siAvay vnoNOvj\[ 3NOaM3Vp S -TIA3Q SHXyVAVg ANN3aN3T3 NOXNV3 AV3JVI Hxnog sNOissag NOSAVJ-N^OHaSg 3:ifi VW3T3ia saavsrivj Hxaog Tiv>i L xasNng NOIXVXg 33NIWON3J\[ OH3NV^ Tg Tf — oc + + + + + + + + + + + ++ + + + ++ + + + + + + ++ + + + + + ++ + ++ + + + + + + + + ++ + + + ++ + + + + + + + + + + ++++ + + + + ++ + + + ++ + + ++ + + + ++ + + + + + + + + + + + ++ + + + + + ++ + + ++ + + + + + + + + + + +++ + ++ + + ++ +++ + + + + + + + + + + + ++ + + + + + + + + + + +++ + + + + + + ++ + + + + + + ++ + + + + + + u .2 < Q o o <: s^ ^^ ^ ^ <^ ^ ." «̂-^ i: p ^ o« ^' W "3 <: "3 »^ w ^ y R , < s y ^55 ? 2 "« 5 ~ ii <=^^ w a :S b-2-20 S S R K 2 ^< 00 cj a.«N > S; fc S: S 2 « <3 « o o ~sj -« -« ,i^ > >^ a o 'S « >o t^j, *-! ^ *-l ^ -s; ~s; -R -« u August, 1955 EvERs: Hill Prairies of Illinois 421 cN "j^ v% vo >^ r^ o •* ' ++ ++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ + + + + + + + +++ + + + + + + + 422 Im.inois Natural History Survey Bulletin Vol. 26, Art. 5 TVJ-OX Ha3>!3 3AV3 + + ++ + + + ^30y XN3WNH3A09 + + + ijmg NiviNfioj ++ + + ++ zioj-s + + + Aai03HJ ++ + + + + + NOSdWVS ++ + + + + + nnvN3y + + + + + + snnj + +++ + + + »3A3WTV^ + + + + + + + y3:i3fi + + + QHnaig HX^O|sj + ++ + + + ^33^3 XnNTVy^ ++ + + + + + VISOa3>l3J^ XSV3HX^O^ + ++ + + ++ >(33H3 anp\[ ++ + + soNi^dg .iimg ++ ++ + + + ++ ONI^dg S1AV3^ + ++ + + + vnoNOVj\[ + 3NOa:i3V3 S^TIA3Q + + ++ S3NaVMS + + + ANN3aNaT3 + ++ + +++ + + + NOXNV3 M3|>^ Hxnos + + + sNOissag + ++ ++ + NOSAV(J-N^OHa3S + + + + ++ SMvq NsaaiH + + + + NVWOfI + + + ^33^13 >iooy + + + + VSHf) + + + + VW3T3ia + + + ++ + S3avsnvj Hxnog TIVHJL X3SNnS + + + NOixvxs a3NiwoNap\[ + OHDNv^ ig + + •S « 5S ^0 J; i^ ^ ;^ W iS -> R -J 13 rj >» "kj ». -J .»-h < O Cl, < < 2 e if 5J <3 ^3 <3 2 R K K 5 5 i; « « 's R ..S -^ "^ 13 "a ~^ -i; -^^ (g ••; I --i ^ "o p^ ) ^ ^ ^ o I « « <3 C/Do -1 >-) ^ ^ ^. -«-«;-«: S."3."3."3 I 2 5 2 •^ ^ ^ %J '5 -5 g K 5 ^^R R R W ii O Q J ^ ^ a, a. August, 1955 EvERS: Hill Prairies of Illinois 423 — r^ 424 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 lVJ,OJ^ ^aa>i3 3AV3 + ++ + + >130>{ XN3WNU3AOr) + + +++ iJ.na NIVJ-NHOJ + + + + + + ++ zj-OJ-s ++ + A3103H^ + + ++ + ++ + NOSdlMVg ++ + + + + ++ + xinvNay ++ + + ++ ++ sxTn_>j + + + + ++ + >IHAaWTVy\ ++ + +4- ++ ++ ++ ++++ ysMNng + ++ + ++ + ++ + 3snopj >130Ta + +++ + + + + VldlONI^lfJ + + + ++ + vnT)nvj.nvH3 + + + + + a-iJ-Hnt^Jvi/yj 3>i3j + + + aa^iaig HxiiOf^ + ++ + +++ + + + »3a^3 xnNTVy^ ++ + + + visoaa^aj/^ j.sv3Hx^O{y[ + + + + M33^3 anj\[ + + soNi^idS jjmg + + + + ONI^dg SIAVa^ + + + + + vnoNovp\[ + + + 3NOflM3Vg S^1IA3Q + + + + S3N^VA\S + + + + + + + ++ ANN3aN313 + + + ++ + NOXNV3 Avajsj Hxnog + SNOISSSg + + ++ + NOSAVJ-N^OH33S + 3-Mv^ N3aaiH NVWOf^ + >i33>13 MOO^ + + VS^Q + + + VW3T3ia + + + S3avsnvj Hxnog + iiv^jL x3SNns + + + ++ + + + NOlXVXg 33NIWON3p\[ + + OHONV^ Tg + + + ; .So ^ . » s S b^R^ •^ ^ ^ Vj <=^":: i- ^ £-~ :i::c 13: la: 5: :^ ^ iCj ^ ^ "" s August, 1955 EvERS: Hill Prairies of Illinois 425 Datithonia spicata (L.) Beauv. ex Roem. & Schult. Poverty oat-grass was observed in rock prairie at Devil's Back- bone. It is usually found in dry woodlands. Elymus canadensis L. Canada wild- rye was found in 16 of the 61 hill prai- ries visited. Elymus virginicus L. Virginia wild- rye was found in three hill prairies. It was more common in the adjacent wood- lands than in prairie areas. Eragrostis capillaris (L.) Nees. Lace- grass, a species of fields, clearings, rock ledges, and glades, was collected from hill prairie areas only on the rocky slope at Fountain Bluff. *Eragrostis cilianensis (All.) Lutati. Stinkgrass was found only on the dis- turbed crest of the bluff-ridge at Clen- denny. Eragrostis spectabilis (Pursh) Steud. Purple lovegrass was found scattered in 17 loess prairies. Festtica octoflora Walt. Six-weeks fes- cue (including the variety tenella) was observed in six hill prairies, either on rocky or loess slopes. It was seen also on limestone ledges at three prairie sites. Hordeum pusillum Nutt. Little barley was found only at Phegley hill prairie. Koeleria cristata (L. ) Pers. Junegrass occurred in scattered patches in 14 hill prairies, but it was never abundant. Leptoloma cognatum (Schult.) Chase. Fall witchgrass, more frequent in sand prairie than in hill prairie, was observed at only two sites. Hidden Lake and Dev- il's Backbone. Melica nitens (Scribn.) Nutt. ex Piper. Three-flower melic, a plant of rocky woods, bluffs, and glades, was found growing at Chautauqua on stony prairie slopes, at Valmeyer and Fults on the rock ledges. MuhJenbergia capillaris (Lam.) Trin. This muhly of rocky or sandy woodlands was found only in rock prairie at Gov- ernment Rock. Muhlenbergia cuspidata (Torr.) Rydb. Plains muhly, a plant of rocky bluffs, sandy woods, and loess hills, was found only in loess at Bluff Springs. Muhlenbergia racemosa (Michx.) B.S.P. This species occurred on loess slopes at Wiersma, on rock-strewn slopes of El Rancho, and on rock ledges at Foun- tain Bluff and Sampson. Panicu?n capillare L. Witchgrass was observed in two hill prairies, Bluff Springs and Richwood. Panicum dichotomum L. This panic grass was collected on the stony slopes at Fountain Bluff. Panicum huachucae Ashe. [P. lanugi- nosum var. fasciculatum (Torr.) Fern.] This prairie species of panic grass was found in five hill prairies on the bluffs of the Mississippi River. Panicum linearifolium Scribn. This species, usually of dry woods, was found on stony slopes of Fountain Bluff and Government Rock. Panicum scribnerianum Nash. [P. oli- gosanthes var. scribnerianum (Nash) Fern.] This species was seen in 27 hill prairies, mostly on loess but occasionally on rocky slopes. Panicum sphaerocarpon Ell. This pan- icum of sandy soil was collected at Pheg- ley hill prairie in loess. Panicum tennesseense Ashe. [F. lanu- ginosum var. fasciculatum (Torr.) Fern.] This plant grew in loess at Me- nominee Station and on stony slopes at Standard. Panicum virgatum L. Switchgrass, common throughout most types of prairie in Illinois, was observed in hill prairie only at South Palisades and Hill-Top. Paspalum stramineum Nash. This spe- cies was found in loess of five hill prai- ries. *Poa compressa L. Canada bluegrass occurred on two loess slopes and also two stony slopes. Poa pratensis L. Kentucky bluegrass was found in more than 20 hill prairies. In some it was locally dominant but more often occurred scattered throughout the prairie area. It becomes dominant in pas- tures, and spreads from them. *Setaria lutescens (Weigel) Hubb. [5. glauca (L.) Beauv.] Yellow bristle- grass, or yellow foxtail, was found at Hidden Lake in loess and on the rock ledges at Valmeyer. *Setaria viridis (L.) Beauv. Green bristlegrass, or green foxtail, was seen on three prairie slopes. It was more common on rock ledges than in hill prairie. 426 Ii.MNOis Natural History Survey Bulletin Vol. 26, Art. 5 Sorghastrum nutans (L.) Nash. In- dian grass was observed in 23 hill prai- ries, usually in loess but occasionally on rocky slopes. It was the dominant grass in prairie at Hill-Top and also in the woodland border at North Pandarmie. Sphenopholis obtusata (Michx.) Scribn. Prairie wedgegrass occurred in loess at Clendcnny. It was seen in woodlands ad- joining other prairies. Sforobolus asper (Michx.) Kunth. This dropseed was observed in 10 hill prairies. It was frequent in loess at Prin- cipia. Sporobolus cryptandrus (Torr.) A. Gray. Sand dropseed was seen in loess at Bielema, Seehorn-Payson, and Chautau- qua prairies. Sporobolus heterolcpis (A. Gray) A. Gray. Prairie dropseed was not common in hill prairie. It was observed on stony slopes at El Rancho and Magnolia and on loess at Northeast Meredosia. Sporobolus neglectus Nash. This an- nual dropseed grew on rocky slopes at Bielema and Clendenny hill prairies. At Clendcnny it grew also on limestone ledges and in the border between prairie and wooded coves. Sporobolus vaginiflorus (Torr.) Wood. This species occurred in loess at Bielema, Wiersma, and Swarnes, on rocky slopes and sandstone ledges at Fountain Bluff, and on limestone ledges at Phegley and Sampson. Stipa spartea Trin. Porcupine grass, of infrequent occurrence in hill prairie, was observed at El Rancho, Balk, and Northeast Meredosia. It is commonly ob- served in flatland prairie. Tridens flavus (L.) Hitchc. {^Triodia flava (L.) Smyth.] Purpletop was found growing in loess at eight hill prairies in central and southern Illinois. Uniola latifolia Michx. Broadleaf uniola, or spike grass, common in open woods in southern Illinois, was found in the disturbed loess prairie at Government Rock. Cyperaceae Carex brevior (Dewey) Mack. A sedge of dry, rocky ground, this plant was collected from 10 hill prairies in northern and central Illinois. Carex glaucodea Tuckerm. [6\ flacco- sperma var. glaucodea (Tuckerm.) Kiikenth.] This sedge was collected from rock prairie at Fountain Bluff. Carex gravida Bailey. This common sedge was observed only at Bluff Springs, on the loess slope. Carex gravida var. lunelliana (Mack.) E. J. Hermann. This variety was col- lected only at Rock Creek, from loess. Carex rneadii Dewey. This sedge was collected on stony slopes at Cave Creek. Carex tnuhlenbergii Schk. This sedge, common in sand prairie, was observed in only four hill prairies. Balk, Standard, Chautauqua, and Fountain Bluff. Carex penusylvanica Lam. A sedge of sterile soil and open woods, this species was collected at Devil's Backbone and Northeast Meredosia. Cyperus filiculmis Vahl. The slender cyperus (including the variety macilen- ius), a plant of dry sandy soil, was seen in 16 hill prairies; its southernmost sta- tion was Fountain Bluff. COMMELIXACEAE Tradescantia ohiensis Raf. [7*. canali- culata Raf.] This spiderwort was seen in 16 hill prairies, growing on loess or stony slopes. Also, it was observed in crevices of limestone ledges at Stotz and South Prairie du Rocher. Tradescantia virginiana L. This spe- cies, which occurs mostly in woods, thick- ets, and meadows, was found on the rocky slopes of Fountain Bluff and Government Rock. JUNCACEAE Juncus dudleyi Wieg. This rush was observed in loess prairie at Chautauqua and Fountain Bluff. Juncus interior Wieg. This species was seen growing on loess slopes at Sunset Trail and on rocky slopes at Standard. Juncus tenuis Willd. [/. niacer S. F. Gray.] This common rush of woodlands was observed only at Oblate Fathers, in loess. LiLIACEAE Allium canadense L. Wild garlic was seen in loess at Oblate Fathers and Allen Lake. August, 1955 EvERs: Hill Prairies of Illinois 427 Allium stellatum Ker. This wild on- ion was found on rocky slopes at Govern- ment Rock and on loess slopes at Fults, Sampson, and Phegley. Its occurrence on loess and stony slopes was nowhere so abundant as on rock ledges at the bases of these slopes. *AUium vineale L. Field garlic was found in two prairies. Sugar Loaf and Phegley. *Asparagus officinalis L. Asparagus was seen at Principia and Oblate Fathers prairies. Camassia scilloides (Raf.) Cory. Lo- cally abundant in some upland prairies of Illinois, wild hyacinth was found in hill prairie at Chautauqua. Xothoscordum bivalve (L.) Britt. False garlic, one of the most frequent plants in thin soil of cliff-tops in the Shaw- nee Hills of southern Illinois, was ob- served on rocky slopes at Cave Creek and Government Rock. Smilax bona-nox L. Fringed green- brier, a dry-woodland species, occurred in prairie at Fountain B^uit and Cave Creek. Smilax hispida Muhl. [5. tamnoides var. hispida (Muhl.) Fern.] Common greenbrier was found in Hidden Lake and Phegley prairies. Smilax rotundifolia L. This woodland species was seen in Phegley, Government Rock, and Cave Creek prairies. Amaryllidaceae Agave virginica L. American aloe was seen on stony slopes at Allen Lake and Cave Creek, and on loess slopes at Fults, Sampson, and Phegley. It was observed also on rock ledges at South Prairie du Rocher and Stotz. The mature plants seem to flower every year. In thin soil on rock, the plants have short vertical stems and leaf-bases that vary in length with the depth of the soil. The fleshy roots radiate horizontally over the rock surface. In places, chiefly on rock ledges, the ro- settes form fair-sized patches. Iridaceae *Belamcanda chinensis (L.) DC. Blackberry-lily, an Asiatic species that is very common on open wooded slopes in Pike and Greene counties, where it forms dense stands on the basal slopes of the bluffs, was found in loess at Walnut Creek and in the woodland border at Swarnes. Sisyrinchium albiduni Raf. This blue- eyed grass was found growing in loess in 1 1 hill prairies, most of them in southern Illinois. Sisyrinchium campestre Bickn. This species occurred in 14 hill prairies in cen- tral and northern Illinois, from El Rancho south to Block House. Orchidaceae Spiranthes cernua (L. ) Rich. Nod- ding ladies'-tresses were seen at Clen- denny, Reavis Spring, Bluff Springs, and Phegley, in each case in loess. They were fairly frequent at Reavis Spring. Salicaceae Populus deltoides Marsh. A few indi- viduals of eastern Cottonwood were found in Ursa and Homan hill prairies. Populus grandidentata Michx. The large-toothed aspen, usually found on wooded bluffs, occurred as small trees in Menominee Station, Hill-Top, and South Palisades hill prairies. Populus treniuloides Michx. Quaking aspen was observed in the prairie at Me- nominee Station, North Savanna, and Balk. It and the large-toothed aspen were "in" but not "of" hill prairie. Salix humilis Marsh. Prairie willow was collected from six hill prairies. JUGLANDACEAE Carya texana Buckl. Buckley's or black hickory (including varieties) is a tree of dry upland woods. Seedlings occasion- ally were found growing on the upper prairie slopes at Valmeyer, Sampson, and Phegley. Here it was found also at the bluft'-top in the woodland border. Juglans nigra L. Small individuals of black walnut were seen in North Sa- vanna, Homan, Fall Creek, Walnut Creek, and North Eldred prairies. Large specimens were never found in prairie, only in the adjacent coves and bluff woods. Betulaceae Corylus americana Walt. American hazel, a species of woods and thickets, 428 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 was seen in hill prairie at Sunset Trail and Ursa. Ostrya viri/itiiana (Mill.) K. Koch. American hop-hornheam was found on four rocky prairie slopes and also on one loess slope. It was usually one of the trees found in w(M)ded coves. Fagaceae Quercus alba L. White oak saplings or small trees were observed in loess prai- rie at Sunset Trail, Hill-Top, and Foun- tain Bluff. Quercus viacrocarpa Michx. At Dev- il's Backbone and Ursa a few saplings of bur oak were found in the prairie. There and at other sites it was found also in the coves. Quercus marilandica Muenchh. Black jack was represented by a few stunted in- dividuals in the rock prairie at Govern- ment Rock. Quercus muhlenbergii Engelm. Yellow or chinquapin oak occurred in 10 prai- ries. It was more abundant in clefts of limestone ledges, in coves, and on lower bluff slopes than in prairies. Quercus stellata Wangh. Post oak oc- curred as scattered individuals in seven prairies. It was common in woodland borders in southwestern Illinois. Quercus velutina Lam. Black oak, like other oaks a woodland species, was found in seven prairies, usually in the borders between prairie areas and upland woods, and occasionally as small solitary trees on the prairie slopes. Ulmaceae Celt is laevigata Willd. Sugarberry, a southern tree, most frequent in bottom- lands, was represented by one specimen in rock prairie at Government Rock. Ulmus alata Michx. Winged elm was found on the stony prairie slopes at Foun- tain Bluff, Government Rock, and Cave Creek. Ulmus rubra Muhl. Very small indi- viduals of slippery elm were found in eight hill prairies. Moraceae Madura poiiiifcra (Raf.) Schneid. Osage orange was observed in the pas- tured loess prairie at Walnut Creek and also in the prairie near woodland at Prin- cipia. In some other localities it was abun- dant in pastured woods on the basal slopes of bluffs. Cannabinaceae ^Cannabis sativa L. Common hemp, abundant in some pastured sand areas of Illinois, was seen at South New Canton, a pastured hill prairie. Santalaceae Coniandra uf/ibellata (L. ) Nutt. [C richardsiana Fern.] Bastard-toadflax was found on 13 loess and 7 rocky prairie slopes from El Rancho and Devil's Back- bone south to Renault. POLYGONACEAE Polygouurii tenue Michx. Slender knotweed was collected from the rocky prairie slopes and the sandstone ledges at Fountain Bluff. Chenopodiaceae Chenopodium leptophyllum Nutt. [C. pratericola Rydb.] The narrow-leaved goosefoot was found in sandy loess at Balk and Rock Creek. Nyctaginaceae Mirabilis nyctaginea (Michx.) MacM. Umbrella-wort was found in only one hill prairie, Devil's Backbone. Caryophyllaceae Cerastium nutans Raf. Nodding mouse- ear chickweed occurred in Valmeyer and Fountain Bluff prairies. *Cerastiurn vulgatum L. Common mouse-ear chickweed was found in loess at Seehorn-Payson. *Saponaria officinalis L. Bouncing-bet was found in loess at Homan. Silene antirrhina L. Sleepy catchfly was observed in nine rock or loess prairies and in crevices of rock ledges at the bases of four prairies. Ranunculaceae /Anemone canadensis L. Meadow anem- one was found in Bielema hill prairie. Anemone cylindrica Gray. The long- fruited anemone occurred in 14 hill prai- ries, mostly in loess. August, 1955 EvERs: Hill Prairies of Illinois 429 Anemone virginiana L. Tall anemone, or thimbleweed, was seen on three loess prairie slopes. Aquilegia canadensis L. Wild colum- bine was found under a red cedar grow- ing in loess at North Savanna. It was frequent on some rock ledges and in ad- jacent rocky woods. Delphinium carolinianuni var. crispum Perry. Blue larkspur was collected at Homan, Hidden Lake, and Sessions, where it was growing in loess. Ranunculus fascicularis Muhl. Tufted or early buttercup was found in Balk and Devil's Backbone prairies. Lauraceae Sassafras albidum (Nutt.) Nees. Sassa- fras occurred as small individuals on four prairie slopes. FUMARIACEAE Corydalis montana Engelm. [C. aurea var. occidentalis Engelm.] This corydalis of rocky woods, prairies, and glades (Palmer (S: Steyermark 1035) was found in the Valmeyer prairie. Cruciferae Arabis lyrata L. This species of rock- cress occurred in loess at North Savanna and Balk, and on rock ledges at Menom- inee Station and Sunset Trail. Draba r'eptans (Lam.) Fern. This small, inconspicuous species of whitlow- cress grew in interstices at eight hill prai- rie stations. *Lepidium canipestre (L.) R. Br. Field peppergrass, or cow-cress, was seen in hill prairie only at Devil's Backbone. *Lepidium densifloruni Schrad. This introduced weed was seen in five of the hill prairies visited. Lepidium virginicum L. Common pep- pergrass, a weedy crucifer, was found in three hill prairies. It was in places more abundant in crevices of rock ledges at the base of a prairie slope than in the prairie itself. Saxifragaceae Heuchera richardsonii R. Br. Alum- root was found in loess and on rocky slopes of 13 hill prairies from El Rancho to Cave Creek. Ribes missouriense Nutt. This com- mon gooseberry, usually of woods and thickets, occurred on the disturbed rocky slope of Bielema prairie. Rosaceae Agrirnonia rostellata Wallr. Agrimony was collected only at Chalfin Bridge near the woodland border of one of the prairie openings there. It is a plant that is usu- ally found in woodlands. A melanchier arborea (Michx. f.) Fern. Serviceberry, usually of wooded hillsides, was observed on the rock-strewn slopes at Government Rock and Foun- tain Bluff. It was seen in crevices and clefts in rock ledges near other hill prai- ries. Crataegus crus-galli L. Cockspur-thorn was found on stony slopes at Cave Creek and in loess at Mud Creek and Pere Mar- quette. In these localities and in others it was found also in the woodland bor- ders. Crataegus engelmanni Sarg. This haw- thorn grew on the rock slopes at Cave Creek. Crataegus mollis (T. & G.) Scheele. Red haw, usually a small tree of thick- ets and woodland borders, occurred in Cave Creek prairie. Fragnria virginiana Duch. Strawberry was collected in loess at Bluf? Springs, Mud Creek, and Northeast Meredosia. Malus ioensis (Wood) Britt. [Pyrus ioensis (Wood) Bailey.] Wild crab, or Iowa crabapple, was found as seedlings in six hill prairies. In the coves it was more frequent and the plants were larger than in the prairie areas. Potentilla arguta Pursh. The tall cin- quefoil grew on stony or loess slopes of nine hill prairies in northern Illinois. Potentilla simplex Michx. Common or old-field cinquefoil was found only at Sunset Trail, in loess. Prunus lanata (Sudw. ) Mack. & Bush. [/*. americana var. lanata Sudw.] This wild plum was found in rock prairie at Cave Creek. At other sites, if present, it occurred in the woodland border. Rosa Carolina L. The pasture rose was found in rock prairie or in loess prairie at 12 sites. It was not common there. It is probably more common in flatland prairie. 430 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 Rosa setigera Michx. One plant of the climbing rose was observed at Phegley ; it was not seen in other hill prairies. This rose is common in woodland borders. Rosa sujjulta Greene. \_R. arkansana var. stiffulta (Greene) Cockerell.] This rose was infrequent on loess slopes in four hill prairies. Rubns flagellaris Willd. The dew- berry was found in one loess prairie, Phegley, near a thicket-covered cove. Riibus frotulosus Bigel. This black- berry was seen on the rocky slopes at Chautauqua prairie. Rubus occidentalis L. Black raspberry was found in the rock prairie at Menomi- nee Station. Leguminosae Amorpha canescens Pursh. Leadplant grew in scattered patches in 23 rock or loess prairies from El Rancho and Devil's Backbone south to Valmeyer. Astragalus canadensis L. This milk- vetch occurred infrequently in loess at North Pandarmie, Principia, and Val- meyer. At Housen it was abundant in the woodland border at the crest of the ridge. Astragalus distortus T. & G. This small milk-vetch was seen in loess, on rocky slopes, and in crevices of the rock ledge, at only one site, the Seehorn-Pay- son prairie. Baptisia leucantha T. & G. Wild in- digo, or prairie false-indigo, common in many of the upland prairies and in open woods of Illinois, was found in only one hill prairie, Hill-Top. Cassia fasciculata Michx. Partridge- pea, common in hill prairies of southern Illinois, less frequent in those of northern Illinois and along the Illinois River, was found in 20 prairies. Cassia nictitans L. This cassia was found in the cherty ridge-top prairie at Tamms, the stony and loess prairies at Fountain Bluff, and the loess prairie at Phegley. Cercis canadensis L. Redbud, usually found on forested rocky slopes of bluffs. also was found in coves of hill prairies. Seedlings or very small trees were found occasionally on loess or rock prairie slopes. Crotalaria sagittalis L. Rattlebox was observed in loess at Hill-Top, Clendenny, and Principia. D esnianthus illinoensis (Michx.) MacM. Illinois- or prairie-mimosa, was found growing in loess of two hill prai- ries, Pere Marquette and Principia. In both sites it was locally abundant. Desmodium canadense (L.) DC. This tick-clover was found only in the rock prairie at El Rancho. Desmodium ciliare (Muhl.) DC. This species was collected at 12 stations from Clendenny south to Cave Creek. At Pheg- ley and Sampson it grew also in the wood- land. Desmodium dillenii Darl.* This spe- cies was found in six hill prairies. Hid- den Lake, Clendenny, Pere Marquette, Valmeyer, Fults, and Fountain Bluf?. Desmodium illinoense Gray. The Illi- nois tick-clover was collected in five hill prairies in central Illinois; all specimens collected were from loess slopes. Desmodium paniculatum (L. ) DC. This species, predominantly of open woods and thickets, was encountered in loess prairie at nine sites. Desmodium sessilifolium (Torr.) T. & G. The sessile-leaved tick-clover was found at 22 sites, usually in loess prairie but occasionally on the rock-strewn slopes. Galactia volubilis (L.) Britt. Milk- pea was collected from rock prairie at Cave Creek and Government Rock. Gleditsia triacanthos L. Honey locust grew in scattered groups in four hill prai- ries. Lespedeza capitata Michx. This bush- clover was a common plant on loess and 1 occasionally on rocky prairie slopes. It J was present in 27 of the 61 sites studied. Lespedeza hirta (L.) Hornem. This lespedeza was collected from the cherty prairie at Tamms and was observed in the woodland border at Government Rock. Lespedeza intermedia (S. Wats.) Britt. This species was found in loess at five prairie sites in southern Illinois. Lespedeza procumbens Michx. Trail- ing bush-clover, a species of rocky woods, *In the treatment of this genus in Gray's Manual, edition 8, this entity has been segregated into two species, Desmodium pirplexum and D. glabellum. August, 1955 EvERs: Hill Prairies of Illinois 431 was encountered in five prairies, where it grew also in the wooded coves. Lespedeza repens (L.) Bart. A few plants of creeping bush-clover were found in Sampson and Ursa hill prairies. X Lespedeza simulata Mack. & Bush. This species was collected from loess prairie at Renault and Fults, also on rocky prairie slopes of the latter. *Lespedeza stipulacea Maxim. Korean clover or lespedeza was seen in 13 hill prairies. At Rock Creek it had been planted ; elsewhere it apparently was an escape from the nearby pasturelands. Lespedeza violacea (L.) Pers. Al- though usually found only in thickets and rocky woods, this lespedeza was seen in five prairies. It was more common, how- ever, in the nearby wooded coves than on the prairie slopes. Lespedeza virginica (L. ) Britt. Slen- der bush-clover, a plant of woods, thick- ets, prairies, and glades, was seen growing in 18 prairie sites, from Clendenny and Richwood south to Government Rock and Cave Creek. *Medicago lupulina L. Black medic, a European species, was observed in East Henry and Mud Creek prairies. *MeHIotus alba Desr. White sweet clover was seen in 25 hill prairies. It ap- peared to have been planted at Clendenny. It formed a very dense stand at Hidden Lake. *Melilotus officinalis (L.) Lam. Yel- low sweet clover was less frequent than white sweet clover; it was found at five prairie sites. Petalostemum candidum (Willd.) Michx. White prairie-clover was col- lected or observed at 19 prairie sites from Government Rock northward. It occurred abundantly in loess prairie at Homan, but at Phegley it was restricted to rocky wooded coves. Petalostemum purpureum (Vent.) Rydb. Purple prairie-clover occurred in 43 prairies from El Rancho and Devil's Backbone south to Government Rock. Psoralea tenuiflora Pursh. The many- flowered psoralea occurred in 27 hill prai- ries from Valmeyer north to Ursa and Standard. In some sites it was the most conspicuous species in early summer. It is a distinctly western species and is very infrequent in Illinois other than in hill prairie. Robinia pseudo-acacia L. Black locust, not native in Illinois, has spread from nu- merous plantations and was seen in four loess prairies. Strophostyles helvola (L.) Ell. This wild bean of sand, rocky woods, or thick- ets was observed infrequently in seven hill prairies. Strophostyles leiosperma (T. & G.) Piper. This species was observed in two places, at Hill-Top and Rock Island 31. Stylosanthes biflora (L.) B.S.P. Pencil- flower, a plant of rocky woods and also glades, was collected at Fountain Blulif on both rocky and loess prairie slopes and at Sampson in loess prairie near a cove. Tephrosia virginiana (L.) Pers. Goats-rue, very common in the sand areas of Illinois, and occasional in dry, open woods with varying soil textures, was col- lected in a rock prairie at Government Rock, where it was abundant also in the woodland border, and in loess prairie at Oblate Fathers, Valmeyer, and Renault. LiNACEAE Linum sulcatum Riddell. This annual flax was observed in loess and occasion- ally in stony soil in 28 hill prairies from Bielema and Magnolia south to Allen Lake. OXALIDACEAE Oxalis stricta L. Upright yellow wood- sorrel grew on rocky and loess prairie slopes at nine sites. It was found in crev- ices of ledges at two additional places. Oxalis violacea L. Violet wood-sorrel was found at 25 sites. In some places it blossomed in spring and again in early autumn. Geraniaceae Geranium carolinianum L. This weedy cranesbill was seen in four hill prairies in southwestern Illinois. Rutaceae Ptelea trifoliata L. Scattered small in- dividuals of wafer-ash grew in 11 hill prairies. This plant was more abundant in coves or on basal slopes of the blufifs than in the prairies. 432 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 Xanthoxyluni americanuni Mill. Prick- ly ash was seen in Balk prairie, where it was growing in loess. The woodlands ad- joininji many other prairies contained this species ; only at Balk had it strayed into the prairie. POLYG.ALACEAE Polygala iiicarnata L. This milkwort was found in loess on the crest of the ridge at Northeast Meredosia. Polygala verticillata L. This species, easily overlooked in its location between tufts of grass, was observed in nine prai- ries from Fountain Bluff northward. EUPHORBIACEAE Acalypha ffracilens Gray. This three- seeded mercury grew on the rocky prairie slopes and sandstone ledges at Fountain Bluff. Chaniaesyce glyptosperma (Engelm.) Small. [Euphorbia glyptosperma En- gelm.] This plant was found in rock prairie at Devil's Backbone. Chaniaesyce maculata (L. ) Small. [Euphorbia maculata L.] Nodding spurge was seen in 14 hill prairies; in none of them was it abundant. Chamaesyce supina (Raf.) Moldenke. [Euphorbia supina Raf.] Milk-purslane was found between the bunches of grass in six hill prairies. It was observed also in crevices of ledges. Croton capitatus Michx. Hogwort was found only at Principia and Edgemont. Croton glandulosus var. septentrionalis Muell. Arg. Sand croton was found only at Bluff Springs and Block House. Croton monanthogynus Michx. Prai- rie-tea, a frequently encountered plant in hill prairie, was observed at 19 sites in central and southern Illinois. Euphorbia corollata L. Flowering spurge, a common plant in prairies, glades, and rocky ground, was found in 36 hill prairies, where it grew in loess and rocky soil. It was found also in some adjacent woodlands. *Euphorbia cyparissias L. Cypress- spurge, or cemetery cypress, was found in the Seehorn-Payson prairie as an escape from a nearby cemetery. Euphorbia obtusata Pursh. This spe- cies was collected at Fults. Foinsettin dentata (Michx.) Small. [Euphorbici dentata Michx.] This weedy species was found in 15 hill prairies. Anacardiaceae Rhus aromatica Ait. Fragrant sumac was seen in 15 hill prairies, either in loess or rocky soil. It was encountered also in some wooded coves as well as in blufif-top woods. Rhus aromatica var. arenaria (Greene) Fern. This variety of the fragrant sumac was found in sandy loess at Bald Bluff, Balk, Bielema, and South Palisades. Rhus copallina L. Shining or dwarf sumac was found in loess at Southwest Edgemont, Chalfin Bridge, Fults, and Phegley. Rhus glabra L. Smooth sumac was a very frequent plant in the hill prairies studied. It was observed on 33 rock and loess prairie slopes. It grew in coves and extended out on the spurs, or it grew in the borders of the bluff-top woods and out in the prairies as isolated individuals. In some places it was very dense and formed a thicket. In a few other places most of the individuals in open groups were dead or dying, a result possibly of fire, or of competition by grasses, competition in- tensified by summer drought. Rhus radicans L. Poison ivy, erro- neously called poison oak, was very abun- dant in woodlands adjacent to most of the hill prairies. It was found at Principia in loess and rock prairie. Aquifoliaceae Ilex decidua Walt. Possumhaw or swamp holly, normally found in bottom- land woods or on basal slopes of bluffs, infrequently on shaded cliffs, was ob- served in a cove at Phegley, 200 feet above the adjacent bottomland. Celastraceae Celastrus scandens L. Bittersweet oc- curred in eight hill prairies that adjoined woods. It occurred also in wooded coves near prairie. Rhamnaceae Ceanothus americanus L. New Jersey tea, a plant of rocky woods, forest bor- ders, and glades, was observed in 12 loess I August, 1955 EvERs: Hill Prairies of Illinois 433 and in 2 rock prairies. It was found also in wooded coves nearby. VlTACE.AE Vitis spp. Stunted individuals of prob- ably four species of ^rape were found in a number of hill prairies. No fruiting vines were found in these hill prairies. Hypericaceae ^Hypericum perforatum L. Common St. John's-wort was found in two loess prairies, Sunset Trail and Bluffs. Hypericum punciatum Lam. Spotted St. John's-wort was observed in five hill prairies in central and southern Illinois. Hypericum sphaerocarpum Michx. Round-fruited St. John's-wort was seen in five prairies. CiSTACEAE Helianthemum bicknellii Fern. Frost- weed, a plant of sand prairie, rocky prai- rie, and glade, was found in sandy loess at Menominee Station and Sunset Trail. Lechea leggettii Britt. & HoUick. This pinweed was observed in loess at Menomi- nee Station. Lechea stricta Leggett. It was seen in hill prairie only at Valmeyer. Lechea villosa Ell. This species was encountered at Principia. ViOLACEAE Viola pedata L. Bird-foot violet was not found frequently. It grew on rocky slopes at Government Rock and in loess at Balk and Devil's Backbone. Viola rafinesquii Greene. [V. kitaibeli- ana var. rafinesquii (Greene) Fern.] Field or wild pansy, a plant of prairies, roadsides, glades, and waste places, oc- curred in five hill prairies. LOASACEAE Mentzelia oligosperma Xutt. Stick- leaf, or few-seeded mentzelia, fig. 28, grew chiefly in crevices of rock ledges ; it grew also on rocky slopes above the ledges. It was collected on ledges at North Pan- darmie, Fults, and Phegley ; on rock prai- rie, as well as ledges, at Seehorn-Payson, Sessions, South New Canton, Swarnes, and \"almeyer. It was not observed in the hill prairies between Swarnes and Valmeyer, nor north along the bluffs east of the Bluff Hall railroad siding in Adams County. In Illinois it is apparently re- stricted to unglaciated bluffs or to those not glaciated since Kansan time. This genus is one of those of chiefly western distribution which reaches its eastern limit in exposed xeric habitats in western Illi- nois. Cactaceae Opuntia rafinesquii Engelm. \_0 . humi- fusa Raf.] The prickly pear was ob- served at 10 sites from Seehorn-Payson south to Phegley. It was found on rock ledges at Seehorn-Payson, Valmeyer, and Stotz; on rocky and loess slopes at Ses- sions, Housen, Chautauqua, Principia, Fults, Sampson, and Phegley. Onagrace.ae Gaura biennis L. Biennial gaura, a plant of prairies, roadsides, and waste places, was collected in Seehorn-Payson, Reavis Spring, Bluff Springs, Valmeyer, and Fults prairies. Oenothera biennis L. Common evening primrose was seen infrequently in eight hill prairies. Oenothera laciniata Hill. This evening primrose was found in 11 hill prairies in central and southern Illinois. Umbelliferae Chaerophyllum sp. An unidentified spe- cies of this genus was found at Clen- dcnny. *Daucus carota L. Wild carrot was collected only at Phegley, where but few plants were found. Polytaenia nuttallii DC. Prairie-pars- ley was found growing in loess prairie and also at the border between prairie and rock ledges. It was collected at Reavis Spring, Chautauqua. \^almeyer, and Fults. Spermolepis inennis (Nutt. ) Math. & Const. This umbellifer was found in loess prairie and on rock ledges at See- horn-Payson. Taenidia integerriina (L.) Drude. Taenidia, or yellow pimpernel, was found on rocky slopes at Cave Creek. It was restricted principally to slopes with sparse cover, or to comparatively bare 434 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 Fig. 28. — Mentzelia oligosperma growing in thin loess just above a limestone cliff, south of New Canton, Pike County. spaces just above or just below slopes. Presumably it cannot compete with vig- orous species. *Torilis japonica (Houtt.) DC. Hedj;e-parsley was found in hill prairie only at Chautauqua. This species seem- ingly is becoming widespread in Illinois. Zizia aurea (L.) Koch. Golden alex- anders, a plant of both prairie and forest, grew in the rock prairie at Cave Creek. CORNACEAE Cornus drummondi Meyer. This dog- wood, common in thickets and in wood- land borders, was observed growing singly or in small thickets in loess prairie at 19 sites. It was common also in the adjoin- ing coves. Cornus fiorida L. Scattered individuals of flowering dogAvood, a very attractive ' plant in springtime, were seen in Swarnes and Cave Creek prairies. J Ericaceae ! Vaccinium arboreum Marsh. Farkle- berry, or tree huckleberry, a plant of rocky woods, was collected in rock prairie at Government Rock. Vaccinium vacillans Torr. Hill or low blueberry, a species of rocky woods, bluffs, August, 1955 EvHRs: Hill Prairies of Illinois 435 and glades, grew on the sandstone ledges and in rock prairie at Fountain Bluff. Prim u LAC EAE Androsace occidentalis Pursh. This species was encountered on the rock ledges at V^almeyer and in the rock prairie at Devil's Backbone. Dodecatheon meadia L. This shooting star, occurring in both prairie and forest in Illinois, was found in loess prairie at Reavis Spring and in the border of prairie and rock ledge at Valmeyer. Ebenaceae Diospyros virginioua L. Persimmon occasionally was found growing as scatter- ed individuals in the hill prairies of south- ern Illinois. Oleaceae Fraxinus americana L. White ash, common in wooded coves, was found in a few hill prairies. Fraxinus nigra Marsh. Black ash was observed in the border between the rock ledge and rock prairie at Principia. It was observed in no other prairie. Gentianaceae Gentiana quinquefoUa L. Stiff gentian was collected in loess at Wiersina. Sabatia annularis (L.) Pursh. Rose gentian, or rose-pink, was collected from rock prairie at Sessions. Apocynaceae Apocynum cannabinum L. Hemp dog- bane, or Indian hemp, chiefly of open woods, glades, prairies, and roadsides, was coUected at Principia and Fountain Bluff. Apocynum sibiricuni Jacq. This dog- bane was found in two prairies, Seehorn- Payson and Ursa. ASCLEPIADACEAE Asclepias amplexicaulis Sm. This milk- weed was collected from eight loess prai- ries. Asclepias hirtella (Pennell) Woodson. [Acerates hirtella Pennell.] Although common in upland prairie in Illinois, it iwas collected in hill prairie only at Edge- tnont. Asclepias quadrifolia Jacq. This wood- land milkweed was seen in rock prairie at Government Rock. Asclepias stenophylla Gray. [Acerates angustifoUa (Nutt.) Dene.] This spe- cies of green milkweed was collected from eight hill prairies in Adams, Pike, and Cal- houn counties. In Illinois, it is appar- ently restricted to hill prairies. Asclepias tuberosa L. Butterfly-weed, common in some upland prairies in Illi- nois, was found in but one hill prairie, Government Rock. It is one of the most attractive prairie plants. It can be suc- cessfully transplanted to home gardens. Asclepias z'erticillata L. Horsetail or whorled milkweed, poisonous to livestock, was found in 18 hill prairies, most of them in northern and central Illinois. Asclepias %'iridiflora Raf. [Acerates vir- idiflora (Raf.) Eaton.] This green milk- weed was common in hill prairies; it was observed in 20 of them. POLEMONIACEAE Phlox bifida Beck. Sand phlox was found in five rocky prairies in southern Illinois, and in five sandy loess prairies in the Illinois River valley. Phlox pilosa L. Downy phlox was found in five hill prairies, on either rocky or loess slopes. BORAGINACEAE *Lappula echinata Gilib. European stickseed was collected at Chautauqua in rock prairie. Lithosperniuni canescens (Michx.) Lehm. This gromwell occurred on 2 rock and 14 loess prairie slopes. Lithospernium croceum Fern. Al- though common in sand prairie in Illinois, this species was collected in only two hill prairies, Seehorn-Payson and North El- dred. Lithospernium incisum Lehm. This nar- row-leaved gromwell was very common in hill prairie from Bielema and Devil's Backbone south to Allen Lake. It was observed in 27 prairies. Myosotis verna Nutt. This forget-me- not was found in the Fountain Blufif prairie. Onosmodium occidentale Mack. False gromwell or marbleseed was seen in seven 436 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 hill prairies from El Rancho and Reavis Spring to Cave Creek. Verb-enAC EAE J'erhena bracteata Lag. 5: Rodr. This vervain, abundant along roadsides, was observed in hill prairie only at Balk. J'erhena canadensis (L.) Britt. This attractive vervain, common on rocky bluffs in Monroe County, was collected at Fults and Renault in that county and at Government Rock in Union County. Verbena simplex Lehm. The narrow- leaved vervain was found growing in seven hill prairies, in either rocky soil or loess. Verbena stricta Vent. Hoary vervain was present in 42 hill prairies from El Rancho and Magnolia to Allen Lake. Labiatae Blephilia ciliata (L.) Benth. Wood mint was collected on the rocky prairie slope at Devil's Backbone. Cunila oriyanoides (L.) Britt. Stone mint was found in the rock prairie and on sandstone ledges at Fountain Bluff, and on a rock outcrop at Government Rock. It was more abundant in adjacent open woods than in prairie areas. Hedeoma hispida Pursh. Rough penny- royal was present in many hill prairies and adjoining rock ledges from Menomi- nee Station and Devil's Backbone south to South Prairie du Rocher. Hedeoma pulegioides (L.) Pers. Amer- ican pennyroyal, common in woodlands, was found in rock prairie at Ursa and in loess prairie at Wiersma. hanthus brachiatus (L.) B.S.P. False pennyroyal grew in 10 rock and loess prairies and on 7 rock ledges from Fall Creek and Magnolia south to Cave Creek. Monarda bradburiana Beck. [M. rus- seliana Nutt. (?)] This species of berga- mot was observed in three rock and three loess prairies in southern Illinois. It was commonly found also in open woods and thickets near hill prairies. Monarda fistulosa L. Wild bergamot, common in prairie vegetation along road- sides and railroads, was seen in 16 hill prairies. Monarda punctata L. Spotted berga- mot, locally abundant in sand prairies and barrens of Illinois, was found in sandy loess at Walnut Creek. *Xepeta cataria L. Catnip was found in hill prairie at South New Canton and Chautauqua. Physostegia j'irginiana (L.) Benth. [P. angustifolia Fern. ( ?)] False dragon- head was found in 16 hill prairies from Sessions and Reavis Spring south to Cave Creek. It was seen in loess and rock prai- rie and occasionally in crevices of rock ledges. Prunella vulgaris L. Selfheal, a com- mon plant of woods, fallow fields, and thickets, was observed growing in loess at Sunset Trail. Pycnanthemum flexuosum (Walt.) B.S.P. This mint of open rocky woods, thickets, and fields was seen in loess at Oblate Fathers. Pycnanthemum pilosum Nutt. This was the common mountain mint in 29 loess prairies from Sunset Trail and Reavis Spring south to Allen Lake. Pycnanthemum virginianum (L. ) Dur. & Jacks. This species was collected at El Rancho, Ursa, and Block House. Salvia pitcheri Torr. [5. azurea var. grandifiora Benth.] Blue sage was col- lected from rock prairie at Cave Creek. This sage is a western species, with the eastern extent of its range from Minne- sota to Kentucky coming through Illinois. Scutellaria leonardi Epling. [5. par- vula var. leonardi (Epling) Fern.] This small skullcap grew in 10 hill prairies, most of them in northern and central Illi- nois. Scutellaria ovata Hill. This skullcap was found in loess prairie at Valmeyer. Scutellaria parvula Michx. This small glandular-pubescent skullcap was seen in 10 rock and loess prairies and in crevices of 7 rock-ledge locations. Teucrium canadense L. This wood- sage was found in small numbers in six loess prairies. Solanaceae Physalis heterophylla Nees. This ground-cherry was seen in seven hill prai- ries. Physalis pubescens L. This pubescent annual ground-cherry was seen at BluflF Springs. August, 1955 EvERS: Hill Prairies of Illinois 437 Physalis virginiana Mill. Virginia ground-cherry was collected from six loess prairies in central and northern Illinois. Solatium carolinense L. Horse-nettle was seen only in pastured loess prairie at Walnut Creek. SCROPHULARIACEAE Aureolaria grandiflora (Benth.) Pen- nell. [Gerardia grandiflora Benth.] False foxglove, a species of woods, openings, and thickets, was observed in loess at Sun- set Trail and Magnolia. Buchnera americana L. Blue hearts, previously reported in Illinois only from Cook and Menard counties, was found in six hill prairies in Calhoun, Monroe, and Randolph counties, Dasistoma macrophylla (Nutt.) Raf. {Seymeria macrophylla Nutt.] Mullein foxglove, commonly found in open woods and thickets, was found growing in loess at Swarnes hill prairie. Gerardia aspera Dougl. This gerardia was seen in at least 17 hill prairies from northern to southern Illinois. Gerardia gattingeri Small. This plant was seen in at least six hill prairies in south-central Illinois. Gerardia skinneriana Wood. This plant of bluffs, sands, and barrens was found in four loess prairies. Gerardia tenuifolia Vahl. This gerar- dia of wooded slopes was found in three hill prairies. Pedicularis canadensis L. Wood-betony or common lousewort was found in loess prairie at North Eldred, where also it was very common in the wooded coves. Penstemon pallidas Small. This pale penstemon was collected from 36 loess and rock prairie slopes and 14 rock ledges in 40 sites from Bielema and Devil's Back- bone to Cave Creek. It was moderately abundant in many of these sites. Scrophularia marilandica L. Usually found in thickets and woodland borders, this figwort was collected from loess prairie at Balk. Synthyris bulla (Eaton) Heller. [If'ul- fenia Barnh. ; Besseya Eaton.] This plant of sandy soil was collected from hill prairie at Bielema and Devil's Backbone, both sites near the margin of the Wiscon- ,sin glaciation. ^Verbascum thapsus L. Common mul- lein was observed in loess or rock prairie, or in crevices of rock ledges, in 17 hill prairies. ^Veronica arvensis L. Corn-speedwell, a common European weed, was found in- frequently in eight hill prairies. J'eronica peregrina L. Purslane-speed- well, another weedy species, was collected from rock prairie at Fountain Bluff. Veronicastrum virginicum (L. ) Farw. Culver's-root, a plant of woods, thickets, and prairies, was observed in seven hill prairies. In none of these was it so com- mon as in flatland prairie. BiGNONIACEAE Bignonia capreolata L. Cross-vine, a southern species, was found as a stray at Cave Creek. Campsis radicans (L. ) Seem. Trumpet- creeper, common in woods, thickets, and fields in southern Illinois, was found in four hill prairies. ACANTHACEAE Ruellia humilis Nutt. Hairy ruellia was found in 30 hill prairies (also occa- sionally in crevices of rock ledges) from Bald Bluff and Devil's Backbone to Cave Creek. Plantaginaceae PIantago aristata Michx. The bracted plantain, a common roadside and open- field weed in compact soils of southern Illinois, was collected from five hill prai- ries, in loess and in rocky soil. Plantago purshii R. & S. This western species of plantain, locally abundant in some sand prairies of the state, was found in sandy loess at Bielema and Bluff Springs. Plantago rugelii Dene. This plantain was seen in loess prairie at Principia and Hill-Top. In both sites it grew in the disturbed portions. Plantago virginica L. Hoary plantain, common in fields and rocky waste places, was found in 20 hill prairies. Rubiaceae Diodia teres Walt. Rough buttonweed was collected from one loess prairie, Stotz. 438 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 Galium aparine L. Cleavers was found in nine hill prairies. It was nowhere very ahundanr in the prairies, but was common in the adjacent woodlands. Galium lircaezans Michx. Wild lico- rice, a plant of thickets and rocky woods, w-as found growing in three hill prairies. Also, it was seen in wooded coves. Galium pilosum Ait. This bedstraw, a plant of thickets and rocky woods, was seen in three loess prairies and one rock prairie in southern Illinois. It was found in wooded coves also. Houstonia lanceolata (Poir.) Britt. l^his species of bluets was found at Cave Creek and Block House. Houstonia loiigifolia Gaertn. This spe- cies was encountered in rock prairie at Fountain Bluff and in loess prairie at Valnieyer. Houstonia nigricans (Lam.) Fern. This narrow-leaved species of bluets was found growing abundantly in hill prairie from Swarnes to South Prairie du Rocher, except at Block House, South Edgemont, Sugar Loaf, and Chalfin Bridge. It was present also at North Eldred, Richwood, and Pere Marquette. Caprifoliaceae Symphoricarpos orbiculatus Moench. Buckbrush, a plant of thickets, pastures, and open woods, was seen in 16 loess hill prairies. It was frequent in the coves; in places it formed open pure stands and was the only shrubby species present. Triosteum perfoliatum L. Horse-gen- tian, or wild coffee, a species of open woods and thickets, was observed in loess prairie at Fall Creek, Reavis Spring, Walnut Creek, and Block House. Viburnutn rufidulum Raf. Southern blackhaw, a small tree or shrub of rocky woods, thickets, and glades, was found in rock prairie at Government Rock and Fountain Bluff. It was found in coves at Phegley and on the rock ledges at Re- nault, Chautauqua, and Clendenny. Campanulaceae Campanula rotundifolia L. [C inter- cedens Witasek.] This bellflower was collected from rock prairie at Bielema. It was also seen on the cliffs at Balk and on sandstone at Fountain Bluff. Specularia perfoliata (L. ) A. DC. V^enus's looking-glass, a plant of fallow fields, prairies, and waste places, was found growing in eight hill prairies. LOBELIACEAE Lobelia spicata Lam. Spiked or pale- spike lobelia was observed in 1 1 loess hill prairies. Lobelia spicata var. leptostachys (A. DC.) Mack. & Bush. [L. leptostachys A. DC] This variety was found in six loess hill prairies, in two of these prairies with the typical form of the species. Compositae *Achillea millefolium L. Yarrow, com- mon in pastures, waste places, along road- sides, and similar places, was found infre- quently in five hill prairies. Agoseris cuspidata (Pursh) Raf. This plant was found in loess prairie at Reavis Spring. Ambrosia coronopifolia T. & G. \_A. psilostachya var. coronopifolia (T. & G.) Farw.] Western ragweed was found in central Illinois hill prairies at Sessions, Reavis Spring, Northeast Meredosia, Bluffs, Walnut Creek, and North Eldred. It is abundant in the sand prairies of Illi- nois. Ambrosia elatior L. {A. artemisiifolia var. elatior (L.) Descourtils.] The com- mon ragweed was found in 12 loess hill prairies. Ambrosia trifida L. Giant ragweed was found in hill prairie only at Chau- tauqua. It was observed in a disturbed part of the rock prairie and was only about 2 feet tall. Antennaria neglecta Greene. This small pussytoes was found between the bunches of grass at Menominee Station, Reavis Spring, Northeast Meredosia, Bluffs, Walnut Creek, and North Eldred. Antennaria plantaginifolia (L.) Hook. This species was seen in seven hill prai- ries. It was more abundant in the adja- cent rocky open woods than in the prairie areas. Artemisia caudata Michx. This worm- wood, frequently encountered in sand prairies, was observed in rocky and sandy loess hill prairies at seven sites in northern and central Illinois. August, 1955 EvERs: Hill Prairies of Illinois 439 Aster anomalus Engelm. This aster, a plant of rocky wooded bluffs, was found in hill prairie at Sessions and Fountain Bluff. Aster azureiis Lindl. The bright blue aster was found in 16 hill prairies from Menominee Station and Reavis Spring south to Chalfin Bridge. Aster ericoides L. (including A. exi- guus Rydb.), This weedy aster was seen in 18 hill prairies. Aster UnariifoUus L. Abundant in sand prairie, this aster was collected from loess prairie at Northeast Meredosia and Bunker. Aster oblongifolius Nutt. The oblong- leaf aster, frequently seen on rocky bluffs, was collected from 36 sites in loess and rock prairies ; also it was observed in crevices of rock ledges, in recesses on small cliffs, and on rocky wooded slopes. It ranged from El Rancho and Devil's Backbone south to Cave Creek. Aster parviceps (Burgess) Mack. & Bush. An aster, possibly this species, was collected from rock prairie at Chautau- qua and from loess prairie at Fall Creek, Seehorn-Payson, and Sessions. Aster patens Ait. The spreading aster was seen in 13 hill prairies from Clen- denny to Cave Creek. Aster pilosus Willd. Heath aster, a weedy species, was present in 16 hill prai- ries. It was not so common there as in flatland prairies. Aster ptarmicoides (Nees) T. & G. White upland aster was found at Wiers- ma and Rock Island 31 prairies. Aster sagittifolius Wedem. The ar- row aster, usually found in open woods, occurred in the rocky prairie at Govern- ment Rock and in loess prairie at Clen- denny. Aster sericeus Vent. Silky aster was collected from 10 loess hill prairies from Bielema and Reavis Spring south to Re- nault. It was not very abundant at these sites. Aster turbinellus Lindl. This aster was found in loess and rock prairie at Foun- tain Bluff. At Government Rock it grew in crevices of rocks, and also in the wood- land border, but not in the prairie. Cacalia atriplicifolia L. Pale Indian- plantain, which grows in a variety of habitats, open woods, thickets, and prai- ries, was encountered in loess prairie at four sites and also in coves at two of these places. Cacalia tuberosa Nutt. This species was seen in loess prairie at Bielema, Balk, Bald Bluff, Swarnes, Sampson, and South Prairie du Rocher. Chrysopsis villosa (Pursh) Nutt, [C. camporum Greene,] Golden aster was found in loess at three sites along the Mississippi and at five along the Illinois River. Coreopsis lanceolata L. Lance coreop- sis was found in rocky soil at Fults ; in loess at Reavis Spring, Vaimeyer, and Fults; and on rock ledges at Fults and Stotz. Coreopsis lanceolata var. villosa Michx. [C. crassifolia Ait.] This variety was found in loess prairie at Vaimeyer, Fults, and South Prairie du Rocher. Coreopsis palmata Nutt. Finger core- opsis occurred in more prairies than the preceding species and variety. It was seen in 1 1 prairies from Sunset Trail and Standard south to Renault, Coreopsis tripteris L, Tall coreopsis was seen in loess prairie at Fountain Bluff, Echinacea pallida (Nutt.) Nutt. Pale coneflower was observed in 18 hill prairies from Bielema and Magnolia south to Cave Creek, Erigeron annuus (L.) Pers, White- top, or daisy-fleabane, common in fallow fields, prairies, and waste places, was ob- served in only two hill prairies, Chau- tauqua and Oblate Fathers, Erigeron canadensis L, Horse-weed or mule tail, a common weed, was ob- served in 16 hill prairips. Erigeron divaricatus Michx. Spread- ing fleabane was found ini a pastured hill prairie, Seehorn-Payson, Erigeron strigosus Muhl, This flea- bane was observed in 40 hill prairies. Possibly it occurred in some of the other prairies that were visited but once during this study, Eupatorium altissimum L. Tall thor- oughwort, common in pastures, rocky hills, thickets, and along roadsides, was observed at 35 sites from Sunset Trail and Magnolia to Cave Creek, 440 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 Gnaphalium obtusifolium L. Catfoot, old-field balsam, or sweet everlasting, was observed in 15 hill prairies, Hciuinthus (iivaricatus L. This sun- flower of dry woods and thickets was seen in 13 hill prairies, often on the upper slopes toward the crests of the ridges. Helianthus mollis Lam. Ashy sun- flower, common in some upland prairies, was collected from loess hill prairie and the woodland border at Clendenny. Helianthus occidentalis Riddell. This sunflower was found growing in loess at East Henry and Bunker. Helianthus rigidus (Cass.) Desf. [H. laetiflorus var. rigidus (Cass.) Fern.] Prairie sunflower was seen in five hill prairies from Swarnes to Renault. Helianthus strutnosus L. This sun- flower was encountered in loess at South- west Edgemont, Valmeyer, and Renault. At Fults and Fountain Bluff it was found in wooded coves. Heliopsis helianthoides (L.) Sweet. The scabrous form [var. scabra (Dunal) Fern.] of sunflower heliopsis was found in loess at Block House. Kuhnia eupatorioides L. False boneset was a common species in hill prairie. It was seen in rock and loess prairies from El Rancho and Devil's Backbone to Cave Creek. Lactuca canadensis L. This wild let- tuce was found in loess at four hill prai- ries. Only a few isolated plants were present at each of these sites. *Lactuca scariola L. Prickly lettuce was seen only in the pastured Walnut Creek prairie. Liatris aspera Michx. This blazing- star or gay-feather was observed in 12 hill prairies from Sunset Trail and Devil's Backbone to Grand Canyon. Liatris cylindracea Michx. The cylin- dric blazing-star was collected from loess prairie at North Eldred, Chautauqua, Principia, Block House, Valmeyer, Fults, and Sampson ; at Sunset Trail it was ob- served in crevices of rock ledges. Liatris scabra (Greene) K. Schum. This species was collected in rock prairie at Cave Creek and Fountain Bluff, where it occurred also in loess prairie and in crevices of the sandstone ledges. At Gov- ernment Rock (in the type locality for this species) it was collected in rocky woodlands. Ratibida pinnata (Vent.) Barnh. Prai- rie coneflower, common in upland prairie, was found in nine scattered hill prairies. Rudbeckia niissouriensis Engelm. This coneflower apparently is restricted in its range in Illinois to Monroe and Ran- dolph counties, where it was found in four hill prairies, Valmeyer, Fults. Sampson, and Phegley (Evers 1951). Rudbeckia serotina Nutt.* Black-eyed Susan was found in 12 hill prairies. It was not common at any of these sites. Senecio pauperculus Michx. This rag- wort was found in loess at Sunset Trail. Senecio plattensis Nutt. Prairie rag- weed was found in scattered hill prairies from North Savanna and Reavis Spring to Stotz. Silphiurn integrifolium Michx. Rosin- weed was found in scattered hill prairies from Fall Creek and East Henry to Cave Creek. Silphiu?n laciniatum L. Compass- plant was collected in four loess hill prai- ries, Swarnes, East Henry, Reavis Spring, and North Eldred. SilphiuTH terebinthinaceum Jacq. This species was found at Valmeyer and Cave Creek. Scattered individuals at Cave Creek can be referred to the variety pin- natifidum (Ell.) Gray. Solidago altissima L. Tall golden rod was found in eight hill prairies from Wiersma to Tamms. Solidago canadensis L. This species was found in loess at El Rancho, Sunset Trail, and Wiersma. Solidago drummondii T. & G. Drum- mond's goldenrod was found in hill prai- rie at North Eldred, Chautauqua, Pheg- ley, and Fountain Bluff. It was collected also from crevices in rock ledges at Rich- wood, Valmeyer, Fountain Bluff, and Government Rock. Solidago niissouriensis var. fasciculata Holz. [5. glaberrima Martens.] Prairie goldenrod was seen at Principia and Tamms. This name was applied by Fernald (1950) to our common black-eycii Susan. He separated it from R. hiria I., on the shape of the basal and cauline leaves. The specific name serotina is used in this paper although fur- ther study of the plant in the field and of herbarium specimens may show it not specilicany distinct from R. hirta L. August, 1955 EvERs: Hill Prairies of Illinois 441 Solidago nemoralis Ait. Field goldtn- rod was found to be the most abundant goldenrod of the hill prairies. It was ob- served in 33 loess and rock prairies in Illi- nois. Solidago petiolaris Ait. This species was found in cherty prairie at Tamms. Solidago radula Nutt. Rough golden- rod was found in 15 hill prairies from North Pandarmie and North Eldred south to Government Rock. Solidago rigida L. Rigid goldenrod, common in flatland prairie remnants, was seen in hill prairie at El Rancho, Reavis Spring, Block House, Valmeyer, Renault, and Government Rock. Solidago speciosa Nutt. Showy gol- denrod was collected from loess prairie at Sunset Trail, Devil's Backbone, and Val- meyer. Solidago ulmifolia Aluhl. Elm-leaved goldenrod, a plant of thickets and open woods, was found in six hill prairies, chiefly in stony soil. *Tragopogon major Jacq. [T. dubius Scop.] This European species was found in the rock prairie at Devil's Backbone. *Tragopogon prate nsis L. Goat's- beard was found in loess prairie at Sunset Trail and Oblate Fathers. Verbesina helianthoides Michx. This crownbeard, usually found growing in dry woods and thickets, was seen in rock prairie at Fountain Bluff and Cave Creek and in loess at Chautauqua and Fountain Bluff. Verbesina virgin ica L. White crown- beard, or tickweed, was collected from rock prairie and woodland borders at Cave Creek. Vernonia baldwiui Torr. This iron- weed was found in loess at six hill prai- ries from Sessions and North Eldred south to Sampson. Vernonia missurica Raf. More gener- ally present in hill prairie than the pre- ceding species, this ironweed was found in 11 loess hill prairies and in some of the adjoining wooded coves. Three hundred ninety-four species and varieties of plants were found by the writer in the hill prairies of Illinois. Of these, 390 were vascular plants distributed among 209 genera and 70 families. The family represented by the greatest numbers of species and genera was the Compositae, 71 species and varieties in 26 genera. Aster was the largest genus; 12 species were rep- resented. The four species of nonvascular plants included two species of the lichen Lecidea, a liverwort, and a moss. Geographical Relations of the Hill Prairie Flora The majority of plant species in Illi- nois hill prairies are presumably of south- eastern origin. Three of the important grass species, Andropogon scoparius, A. gerardi, and Sorghastrum nutans, came from southeastern United States. There are, however, numbers of species characteristic of the western plains and of the Ozark plateau. These are Bouteloua hirsuta, Psoralea tenuiflora, Polytaenia nuttalia, Asclepias stenophylla, Mentzelia oligospernia. Salvia pitcheri, Plan tag o purshii, Agoseris cuspidata, Ambrosia coronopifolia, Solidago drummondii, Aster anomalus, and Rudbeckia missouriensis. The last three possibly are from the Ozark plateau. In addition to the plants enumerated above, Synthyris bullii may be mentioned as a species, possibly from the Rocky Mountains, that migrated east- ward along glacial moraines (Pennell 1935). SUMMARY 1. Hill prairies are grasslands on pro- nounced slopes. Prairies is here used as a vegetational term rather than a locational or topographic term for an expansive flat. 2. Of the many hill prairies in Illinois, 61, with a combined area of more than 200 acres, were visited by the writer in the course of this study. 3. In Illinois, hill prairies occur on the exposed upper or brow slopes of the generally southwest- and west-facing bluffs east of the Mississippi River for most of the length of the state and on similar slopes along the Illinois River from Putnam County southward into Jersey County, where the valley of the Illinois enters the Mississippi valley. Hill prairies are present also along the Sangamon and Rock rivers. 4. Location and topography exert the strongest controls, or place influences, that 442 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 determine the occurrence of prairie on the upper slope of a bluf?. The west- to southwest-facing position of the slope, which exposes the slope directly to the hot rays of the afternoon sun and to prevail- ing southwest summer winds, and the alti- tude of the bluft and width of the adja- cent bottomlands help to provide the ex- tremely xeric conditions under which this type of prairie thrives. Rapid and exces- sive drainage, due both to slope and to permeable loess substratum, is a reinforc- ing condition. 5. The vegetation of Illinois hill prai- ries is the bunch-grass type, with Andro- pogon scoparius the dominant species in most stands. Bouteloua curtipendula is usually present, in a few prairies dom- inant. In a few hill prairies, Sorghostrum nutans and a few other bunch grasses oc- cur frequently and may dominate small areas within the prairie, or, rarely, the entire stand. 6. For detailed studies of the vegeta- tion, plots were staked in unpas|:ured and in pastured variants of the same prairie slope. Data were obtained frop plot sizes ranging from 1 '256 milacre to 9 milacres. The smallest size found to be effective was 1/64 milacre. The largest area staked in each prairie was 75 milacres. One mil- acre in each prairie—pastured and unpas- tured—was mapped. All plant individ- uals were charted and counted in each of these milacres. Species lists were compiled for plots of the several sizes. 7. In the mapped milacre of the un- pastured prairie, the estimated number of plants was 1,949; 1,404 of these were An- dropogon scoparius. In the mapped mil- acre of the pastured prairie, the estimated number of plants was 1,341 ; 849 of these were A. scoparius. 8. The ground space occupied by plants in the mapped milacre of the un- pastured prairie was 1,884,1 square inches, of which 1,781.0 square inches were occupied by Andropogon scoparius. In the mapped milacre of the pastured prairie the ground space occupied by plants was found to be 1,403.3 square inches, of which 1,107.0 square inches were occupied by A. scoparius. In the un- pastured prairie, at ground surface, 69.96 per cent of the mapped milacre was bare loess; in the pastured prairie, 77.63 per cent. 9. In the mapped milacre of the un- pastured prairie, foliage covered 4,988 square inches, approximately 80 per cent of the milacre. In the mapped milacre of the pastured prairie, foliage covered 2,525 square inches, about 40 per cent of the milacre. In both pastured and unpastured prairie, Andropogon scoparius was the species with the largest foliage area. In the unpastured milacre, approximately 20 per cent of the ground was not covered by foliage; in the pastured milacre, about 60 per cent. 10. The available space per plant in the unpastured milacre was found to be 3.22 square inches; in the pastured mil- acre it was 4.68 square inches. 11. For the study of frequency of oc- currence of species in plots within hill prairie, a good distribution of species was obtained with quadrat sizes of 1/64 to 1/4 milacre in unpastured prairie; 1/16 to 1/4 milacre in pastured prairie. 12. From species-area curves, the smallest representative area—the smallest one-piece area having some claim to be representative—was determined for the unpastured prairie as 0.76 milacre, and, for the pastured, 1.26 milacres. The min- imum area for assignment to type—an area that is large enough to include all the important and a moderate number of mi- nor species—was determined as 3.80 mil- acres for the unpastured and 6.30 mil- acres for the pastured prairie. The fair- sized stand—an area that is 50 times as large as the smallest representative area and contains twnce as many species-—was 38.0 milacres for the unpastured and 63.0 milacres for the pastured hill prairie. 13. The flora of 36 hill prairies was used as a basis for presence studies. The "constants" (species in 29, 80 per cent, or more of the 36 locations) of this type of prairie in Illinois were Andropogon sco- parius, Erigeron strigosus, Bouteloua cur- tipendula, Petalostemum purpureum. Eu- phorbia coroUata, Pensternon pallidus, A. gerardi. Verbena stricta, and Kuhnia eu- patorioides. Twenty-five species were found in 18 or more of the 36 prairies used in this study of presence. Species most characteristic of the hill prairie type August, 1955 EvERS: Hill Prairies of Illinois 443 (i.e., of much lower presence in other prairie types in Illinois) were Bouteloua curtipendula, Psoralen tenuiflora, Petalo- steniuni ca7ididum, Linum sulcatum, and Lithospermurn incisum. 14. Prairie stands possibly existed on the bluffs that now support prairie from Wis- consin or pre-Wisconsin time to the pres- ent. This vegetation will presumably con- tinue to grow on these sites until a change in climate occurs which will provide more mesic conditions, or until advanced erosion of the bluffs forms a continuously gentle slope, or until high cliffs are reduced. 15. The observed flora of Illinois hill prairie was 394 species and varieties. Of these, 390 were vascular plants distributed in 209 genera and 70 families. The larg- est family was Compositae, with 2b gen- era and 71 species and varieties. Aster was the largest genus, with 12 species. Thirty species were of foreign origin. 16. Although most species of Illinois hill prairie plants are of southeastern ori- gin, nine species are distinctly western or southwestern, and three are from the Ozark plateau. Of these 12 species, Aient- zelia oligospernia, Asclepias stenophylla, and Rudbeckia rnissouriensis are seemingly restricted to hill prairie and adjacent rock ledges. 17. Some prairie slopes are grazed, and some are annually or less frequently burned, yet the prairie persists. As these steep slopes have never been plowed, they represent one of the least disturbed types of prairie in Illinois, and some of them should be preserved. LITERATURE CITED Buth, B. F. 1895. Notes on the mound riora of Atchison County, Missouri. Mo. Hot. Gard. Ann. Rep. 6:121-34. Chamberlin, T. C. 1897. Supplementary hypothesis respecting the origin of the loess of the Mississippi Valley. Jour. CJeol. 5(8) :795-802. Costello, David F. 1931. Comparative studv of river bluff succession on the Iowa and Nebraska sides of the Missouri River. Bot. CJaz. 91 : 295-307. Deam, Charles C. 1940. Flora of Indiana. Department of Conservation, Division of Forestry, Indianapolis, Indiana. 1,236 pp. Ellsworth, H. L. 1837. Illinois in 1837. S. A. Mitchell, Philadelphia. 143 pp. Evers, Robert A. 1951. Four plants new to the Illinois flora. Rhodora 53(628) : 111-3. Fernald, Merritt Lyndon 1950. Gray's Manual of Botany. Ed. 8. American Book Company, New York. 1,632 pp. Gates, Frank Caleb 1912. The vegetation of the Beach area in northeastern Illinois and southeastern Wisconsin. 111. Lab. Nat. Hist. Bui. 9(5) :255-372. Gleason, Henry Allan 1910. The vegetation of the inland sand deposits of Illinois. 111. Lab. Nat. Hist. Bui. 9(2):23-174. [1923.] The vegetational history of the Middle West. Assn. Am. Geog. Ann. 12:39-85. (Vol- ume dated 1922.) 1952. The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. Vol. 1. The Pteridophyta, Gymnospermae and Monocotyledoneae. New York Botanical Garden [New York, N. Y.]. 482 pp. Hanson, Herbert C. 1922. Prairie inclusions in the deciduous forest climax. Am. Jour. Bot. 9(6):330-7. Hitchcock, A. S. 1950. Manual of the grasses of the United States. Ed. 2 (revised by Agnes Chase). U. S. Dept. Ag. Misc. Pub. 200. 1,051 pp. Hopkins, Harold H. 1951. Ecology of the native vegetation of the loess hills in central Nebraska. Ecol. Monog. 21(2):125-47. Hus, Henri 1908. An ecological cross section of the Mississippi River in the region of St. Louis, Missouri. Mo. Bot. Gard. Ann. Rep. 19:127-258. Jones, George Neville 1950. Flora of Illinois. Ed. 2. University of Notre Dame Press, Notre Dame, Indiana. 368 pp. Korstian, Clarence F., and Theodore S. Coile 1938. Plant competition in forest stands. Duke Univ. Forestry Bui. 3. 125 pp. Leighton, Morris M., and H. B. Willman 1950. Loess formations of the Mississippi Valley. Jour. Geol. 58(6) : 599-623. Leonard, A. Byron 1952. Illinoian and Wisconsinian molluscan faunas in Kansas. Kans. Univ. Paleontol. Con- trib., Mollusca 4. 38 pp. Leonard, A. Byron, and John C. Frye 1954. Ecological conditions accompanying loess deposition in the Great Plains region of the United States. Jour. Geol. 62(4) :399-404. [444] I August, 1955 EvERs: Hill Prairies of Illinois 445 Marks, John B. 1942. Land use and plant succession in Coon Valley, Wisconsin. Ecol. Monog. 12(2) :113-33. Page, John L. 1949. Climate of Illinois. 111. Ag. Exp. Sta. Bui. 532:93-364. Palmer, Ernest J., and Julian A. Steyermark 1935. An annotated catalogue of the flowering plants of Missouri. Mo. Bot. Gard. Ann 22(3) :375-758. Pammel, L. H. 1896. Notes on the flora of western Iowa. Iowa Acad. Sci. Proc. 3:106-35. 1899. Some ecological notes on the Muscatine flora. Plant World 2(ll):182-6. 1902. Preliminary notes on the flora of western Iowa, especially from the physiographical ecological standpoint. Iowa Acad. Sci. Proc. 9:152-80. Peck, J. M. 1834. A gazetteer of Illinois. R. Goudy, Jacksonville [Illinois]. 376 pp. Pennell, Francis W. 1935. The Scrophulariaceae of eastern temperate North America. Acad. Nat. Sci. Phila. Monog. 1. 650 pp. Russell, Richard Joel 1944. Lower Mississippi Valley loess. Geol. Soc. Am. Bui. 55(l):l-40. Sargent, C. S. 1889. Portions of the journal of Andre Michaux, botanist, written during his travels in the United States and Canada, 1785 to 1796. With an introduction and explanatory notes by C. S. Sargent. Am. Philos. Soc. Proc. 26(129) :1-145. Shaffer, Paul R. 1954. Extension of Tazewell glacial substage of western Illinois into eastern Iowa. Geol. Soc. Am. Bui. 65(5) :443-56. Shimek, B. 1896. A theory of the loess. Iowa Acad. Sci. Proc. 3:82-9. 1903. Living plants as geological factors. Iowa Acad. Sci. Proc. 10:41-8. 1910a. Geology of Harrison and Monona counties. Iowa Geol. Surv. Ann. Rep., 1909, 20:271-485. 1910^. Prairie openings in the forest. Iowa Acad. Sci. Proc. 17:16-9. 1911. The prairies. Iowa Univ. Lab. Nat. Hist. Bui. 6(2) : 169-240. 1924. The prairie of the Mississippi River bluffs. Iowa Acad. Sci. Proc. 31:205-12. Short, C. W. 1845. Observations on the botany of Illinois, more especially in reference to the autumnal flora of the prairies. West. Jour. Med. and Surg., n.s., 3:185-98. Smith, Guy D. 1942. Illinois loess—variations in its properties and distribution: a pedologic interpretation. 111. Ag. Exp. Sta. Bui. 490:137-84. Steiger, T. L. 1930. Structure of prairie vegetation. Ecology 11 ( 1 ): 170-217. Steyermark, Julian A. 1940. Studies of the vegetation of Missouri— I. Natural plant associations and succession in the Ozarks of Missouri. Field Mus. Nat. Hist. Bot. Ser. 9( 5) :347-475. Turner, Lewis M. 1934fl. Grassland in the floodplain of Illinois rivers. 111. Acad. Sci. Trans. 26(3):71-2. 1934//. Grassland in the floodplain of Illinois rivers. Am. Midland Nat. 15(6) :770-80. Udden, J. A. 1894. Erosion, transportation, and sedimentation performed by the atmosphere. Jour. Geol. 2(3) :318-31. Vestal, Arthur G. 1913. An associational study of Illinois sand prairie. 111. Lab. Nat. Hist. Bui. 10(1) :l-96. 1918. Local inclusions of prairie within forest. 111. Acad. Sci. Trans. 11:122-6. 446 Illinois Natural History Survey Bulletin Vol. 26, Art. 5 1931. A preliminary vegetation map of Illinois. 111. Acad. Sci. Trans. 23(3) :204-17. 1945. Flora of Illinois. [A review of a book with that title.] Science, n.s., 102(2656) : 542-3. 1949. Minimum areas for different vegetations: Their determination from species-area curves. 111. Biol. Monog. 20(3):1-129. Vestal, A. G., and H. Bartholomew 1941. Prairie of loess bluffs of the Illinois River. (Abs.) Ecol. Soc. Am. Bui. 22(4) :41. Vestal. Arthur G., and Mary Frances Heermans 1945. Size requirements for reference areas in mixed forests. Ecology 26(2) : 122-34. Woodard, John 1924. Origin of prairies in Illinois. Bot. Gaz. 77(3) :241-61. Worthen, A. H. 1868. Geological survey of Illinois. Vol. 3. Geology and palaeontology. [Illinois Geological Survey, Springfield.] 574 pp. SOME RECENT PUBLICATIONS A-—ILLINOIS NATURAL HISTORY SURVEY BULLETIN. Volume 25, Article 1.—Characteristics of Residual Insecticides Toxic to the House Fly. Willis N. Bruce. July, 1949. 32 pp., frontis. + 14 figs., bibliog. 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