Vascular Plant Communities of the Green River Lowlands in Northwestern Illinois John E. Ebinger, Loy R. Phillippe, William C. Handel, Connie J. Cunningham, William E. McClain, Randy N. Nyboer, and Todd Bittner Illinois Natural History Survey Bulletin Volume 39, Article 2 October 2009 Institute of Natural Resource Sustainability Institute of Natural Resource Sustainability William Shilts, Executive Director Illinois Natural History Survey Brian D. Anderson, Director Forbes Natural History Building 1816 South Oak Street Champaign, Illinois 61820 217-333-6880 Citation: Ebinger, J.E., L.R. Phillippe, W.C. Handel, C.J. Cunningham, W.E. McClain, R.N. Nyboer, and T. Bittner. 2009. Vascular plant communities of the Green River Lowlands in northwestern Illinois. Illinois Natural History Survey Bulletin 39(2):39–78. Science editor: Jeff Levengood Production editor: Charles Warwick US ISSN 0073-4918 US ISBN 1-882932-23-4 Printed by authority of the University of Illinois © 2009 PO# 8073131—.45M—10-09 Printed with soy ink on recycled and recyclable paper. The University of Illinois will not engage in discrimination or harassment against any person because of race, color, religion, national origin, ancestry, age, marital status, disability, sexual orientation including gender identity, unfavorable discharge from the military or status as a protected veteran and will comply with all federal and state nondiscrimination, equal opportunity and affirmative action laws, orders and regulations. This nondiscrimination policy applies to admissions, employment, access to and treatment in University programs and activities. University complaint and grievance procedures provide employees and students with the means for the resolution of complaints that allege a violation of this Statement. Inquiries or complaints may be addressed to the Director and Assistant Chancellor, Office of Equal Opportunity and Access, 601 East John Street, Swanlund Administra- tion Building, (217) 333-0885, fax (217) 244-9136, TTY (217) 244-9850 or the Associate Provost and Director, Academic Human Resources, Henry Administration Building, (217) 333-6747, fax (217) 244-5584. For other University of Illinois information, contact University Directory Assistance at 333-1000. Vascular Plant Communities of the Green River Lowlands in Northwestern Illinois John E. Ebinger1, Loy R. Phillippe1, William C. Handel1, Connie J. Cunningham1, William E. McClain1, Randy N. Nyboer1, and Todd Bittner2 Correspondence to: John E. Ebinger Illinois Natural History Survey 1816 S. Oak St., Champaign, IL 61820 217-581-3624 jeebinger@eiu.edu 1. Illinois Natural History Survey 1816 S. Oak St., Champaign, IL 61820 2. Illinois Department of Natural Resources: Current address— Cornell Plantations, 1 Plantations Rd., Ithaca, NY 14850 ii Vascular Plant Communities of the Green River Lowlands in Northwestern Illinois John E. Ebinger, Loy R. Phillippe, William C. Handel, Connie J. Cunningham, William E. McClain, Randy N. Nyboer, and Todd Bittner iii Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 Study Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40 Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 Vascular Plant Species and Communities . . . . . . . . . . . . . . . . . . . . . . . . .41 Ground Layer Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 Forest Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 Dry Sand Prairie. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 Dry-mesic Sand Prairie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 Mesic Sand Prairie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 Wet Sand Prairie. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45 Sedge Meadow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45 Marsh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47 Phalaris Vegetation Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47 Typha/Persicaria Vegetation Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . .47 Bolboschoenus fluviatilis Vegetation Zone . . . . . . . . . . . . . . . . . . . . . .47 Sparganium eurycarpum Vegetation Zone . . . . . . . . . . . . . . . . . . . . . .49 Carex lacustris/Persicaria coccinea Vegetation Zone . . . . . . . . . . . . .49 Sand Pond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 Sand Forest. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52 Exotic Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52 Endangered Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54 Dry Sand Prairie. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54 Dry-mesic Sand Prairie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58 Mesic Sand Prairie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59 Wet Sand Prarie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59 Sedge Meadow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59 Marsh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59 Sand Forest. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59 Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61 Appendix 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64 iv Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 39 ABSTRACT A few high-quality prairies still exist in the sand deposits of the Green River Lowlands. The most extensive remnants are in the Green River State Wildlife Area, Lee County, Illinois. Three upland prairie communities were surveyed; a dry sand prairie dominated by Schizachyrium sco- parium, Ambrosia psilostachya, and Amorpha canescens; a dry-mesic sand prairie dominated by Sorghastrum nutans, Schizachyrium scoparium, Antennaria plantaginifolia, and Liatris aspera; and a mesic sand prairie where Sorghastrum nutans and Andropogon gerardii were the dominant grasses, and Parthenium integrifolium, Fragaria virginiana, Liatris pycnostachya, and Euthamia gymnospermoides the common forbs. The lowlands, which included approximately 325 ha, were dominated by the exotic Phalaris arundinacea, but high-quality wet sand prairie, sedge meadow, and marsh communities existed. The wet sand prairies were dominated by Spartina pectinata, Helianthus grosseserratus, and Solidago canadensis; the sedge meadows were dominated by Carex haydenii, Calamagrostis canadensis, and Persicaria coccinea; the marsh communities were divided into distinct vegetation zones. These vegetation zones were surveyed in 2002 and subject- ed to an extensive uncontrolled fire in 2005. Surveys completed in 2006 and 2007 were used to determine successional changes resulting from the fire. These studies suggested that most commu- nities were returning to the species composition found before the 2005 fire. INTRODUCTION Sand deposits are relatively common in the northern half of Illinois, accounting for about 5% of the land area of the state. Most occur on glacial outwash plains resulting from erosion events associated with Wisconsin glaciation (Wildman and Frye 1970, King 1981). One extensive sand deposit is the Green River Lowlands in parts of Bureau, Henry, Lee, and Whiteside counties in northwestern Illinois. Located just to the west of the terminal moraine of Wisconsin glaciation, extensive amounts of sand and gravel were deposited in these areas during intermittent warm periods of the Wisconsin Episode (Killey 1998). These sands were reworked by wind, creating numerous small sand dune fields (Willman and Frye 1970). These sand deposits are scattered throughout the Green River Lowland Section of the Grand Prairie Natural Division (Schwegman 1973). This section, which includes the broad valley of the Green River and lower Rock River, was formed about 10,000 years ago during the retreat of Wisconsin glaciation (Willman and Frye 1970). During early European settlement this section had extensive marshes and wet prairies associated with the Great Inlet Swamp that covered part of Lee County (Lyman 1901, McClain 1992, McClain and Ebinger 2000). Sand deposits containing numerous small dunes were common. Forests and savanna communities grew on the dry sandy ridges, while floodplain forests occurred along the rivers. In recent history, grazing, drainage, and cultivation have disturbed nearly all of this section, while fire suppression has resulted in the formation of many poor-quality sand forests containing numerous early successional and non-native (exotic) species. Gleason (1910) referred to the vegetation of the Green River Lowlands in his extensive study of the Illinois sand deposits. Until recently that study was the only reference available of the flora of this region. Phillippe et al. (2000, 2003) studied some of the sand prairie communities at the Green River State Wildlife Area (GRSWA), Handel et al. (2003) examined the sand prairie remnants and sedge meadows of the Richardson Wildlife Foundation, a private hunting club, and McClain et al. (2003) examined the vegetation of a dune ridge at Foley Sand Prairie Nature Preserve. The purpose of the present study was to determine the composition and structure of the vegetation of the sand communities present in the GRSWA. Also, as the result of an extensive uncontrolled fire in the marsh community of the GRSWA in 2005, we examined the changes in the vegetation of this area in 2006 and 2007. Vol. 39 Art. 240 Illinois Natural History Survey Bulletin STUDY AREA The GRSWA, located in the southwestern part of Lee County, about 23 km south of Dixon, Illinois (S7, S8, S17, S18, T19N R9E and S12, S13 T19N R8E), is the most extensive area in public ownership in the Green River Lowlands (Ebinger et al. 2008) (Fig. 1). The initial purchase of land started in 1938 under the Federal Aid in Wildlife Restoration Act to provide habitat for waterfowl and dwindling populations of the Greater Prairie Chicken (Tympanuchus cupido). Subsequent land purchases increased the size of the GRSWA to 1,025 ha (2,533 acres). The area was under intense grazing pressure prior to 1938, and was subject to much brush encroachment resulting from fire suppression until 1987. Much of the grasslands of the GRSWA were mowed annually from June through September until 1998 (Todd Bittner, personal observations). During the natural areas inventory in the mid-1970s no high-quality natural areas were reported for the GRSWA (White 1978). Since 1993 an active management program at the GRSWA has been implemented, including burning, brush removal, restoration plantings, and exotic species control. In addition to prescribed fire used to manage the prairie communities, most of the forested areas, Figure 1. Location of the Green River State Wildlife Area (GRSWA) in the Green River Lowland Section (GRLS) of the Grand Prairie Natural Division, about 24 km south of Dixon, Lee County, Illinois . Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 41 including the woody understory, were removed in the fall and winter of 2001. Beginning in 1987, many of the the dry, dry-mesic, and mesic sand prairies were intentionally burned every one to three years. Presently this multiple- use area is managed for the protection and enhancement of wildlife and natural heritage resources. The soils of the uplands at the GRSWA are Billett fine sandy loam, Chelsea fine sand, and Sparta loamy sand (Zwicker 1985). These soils, which occur on side slopes and ridges of dunes, are relatively low in organic matter, well drained, and have a surface layer of dark gray to yellow brown friable fine sand. The wetland soils are Adrian muck, Gilford fine sandy loam, Orio mucky sandy loam, and Orio sandy loam. Very high in organic material, these soils occur on level, poorly drained outwash plains and contain surface water for much of the winter and early spring. On 18 October 2005 the extensive marsh located at the western portion of the GRSWA was burned in an attempt to decrease the growth of the exotic species Phalaris arundinacea (Lavergne and Molofsky 2006). Dry conditions at the time of the controlled burn resulted in extensive peat fires, some of which continued to burn for approximately 30 days. Water was pumped into some areas of the marsh from cen- tral pivot irrigation wells located on surrounding farms, and some fires were repeatedly disked and flooded. The climate in northwestern Illinois is con- tinental with warm summers and cold winters. Based on weather data from Dixon, located near the north-central edge of the Green River Lowlands, the mean annual precipitation is 94.7 cm, June having the highest rainfall (12.4 cm), and February the lowest (3.6 cm). Mean annual temperature is 8.5oC with the hottest month being July (average of 22.3oC), and the coldest January (average of –7.9oC). There are an aver- age of 161 frost-free days (Midwestern Regional Climate Center 2008). METHODS Vascular Plant Species and Communities: The natural areas studied were visited at various times throughout the growing seasons of 2000 through 2007. Voucher specimens of each plant species were collected, identified, and deposited in the herbarium of the Illinois Natural History Survey, Champaign, Illinois (ILLS), and the Stover-Ebinger Herbarium of Eastern Illinois University, Charleston, Illinois (EIU). Criteria for designating non-native species followed Mohlenbrock (2002), Gleason and Cronquist (1991), and Taft et al. (1997). Nomencla- ture follows Mohlenbrock (2002). The plant communities encountered were designated and plotted using the classification system of White and Madany (1978). The locations of threatened and endangered plant species were recorded (Herkert and Ebinger 2002). The Floristic Quality Index (FQI) was determined for each community type using the coefficient of conservatism (CC) assigned each species based on a species tolerance to disturbance and its fidelity to habitat integ- rity (Taft et al. 1997). The FQI, therefore, is a weighted index of species richness (N = number of species present on a site), and is the arithmetic product of the average coefficient of conservatism (C-Value = the average of all species CCs) multiplied by the square root of the species richness (√N) of an inventory site: FQI = C-Value (√N). For relatively small areas that are intensively studied, the FQI gives a rapid means of comparison and an indication of the floristic integrity of the site. Using the FQI along with other floristic measures, such as quadrat-based sampling methods, provide a way to make comparisons among sites. Prai- ries with an FQI of 35 or higher are considered high-quality natural areas (Taft et al. 1997). All species recorded for the plots as well as all other species observed in the community were used to determine the FQI of each site. The Sorensen Index of Similarity (ISs) was used to determine the degree of vegetation similarity among the prairie areas surveyed throughout the Mississippi River sand deposits (Mueller-Dombois and Ellenberg 1974). In this index [ISs = 2C/(A+B) x 100], where A equals the number of species in the first community, B equals the number of species in the second community, while C equals the number of spe- cies common between the two communities. Ground Layer Sampling: In mid-summer of 2003 through 2007 line transects were located randomly along cardinal compass directions within the sand prairies, sedge meadows, and marsh communities. Many of the sites were sampled two or three times during the study; the starting points of each transect were Vol. 39 Art. 242 Illinois Natural History Survey Bulletin marked with metal stakes and relocated using GPS coordinates during each survey. The dry, dry-mesic, mesic, and wet sand prairies were surveyed once (2006), whereas the marsh com- munities were surveyed in 2002, and again in 2006 and 2007 after a very hot uncontrolled fire burned the marsh in 2005. The sedge meadow located next to a wet sand prairie was surveyed in 2006, and the sedge meadow associated with the marsh in 2002, 2006, and 2007. Two transects were randomly located within each community; along each transect, 1m2 plots were located at 1- or 5-m intervals (on larger sites the plots were more widely spaced) on alternating sides of the transects (n=50). A random numbers table was used to deter- mine the number of meters (0 to 9) a plot was located from the transect line. Species cover was determined using the Daubenmire (1959) cover class system as modified by Bailey and Poulton (1968). Only ground layer species rooted within the plot frame were recorded. The modified Daubenmire cover scale is as follows: class 1 = 0 to 1%; class 2 = >1 to 5%; class 3 = >5 to 25%; class 4 = >25 to 50%; class 5 = >50 to 75%; class 6 = >75 to 95%; class 7 = >95 to 100%. Importance value (IV) was determined by summing relative cover and relative fre- quency. The location of the community study sites are shown in Figure 2 along with extent of the marsh at the GRSWA and the area burned in 2005. Forest Sampling: In the summer of 2001 the overstory of the forests at the GRSWA were sampled using circular plots 0.3 ha in size, spaced at 25-m intervals along line transects (n=10). Within each plot all living individuals >10.0 cm dbh were identified and diameters recorded. From these data, living-stem density (stems/ha), basal area (m2/ha), relative density, relative dominance, importance value (IV), and average diameter (cm) were calculated for each species. Determination of the IV followed the procedure used by McIntosh (1957), and is the sum of the relative density and relative domi- nance (basal area). Woody understory composi- tion and density (stems/ha) were determined using nested circular plots 0.0001, 0.001, and 0.01 ha in size, located at 15-m intervals along randomly located east-west transects within each study area. Four additional 0.0001-ha Figure 2. The location of the community studied at the GRSWA along with extent of the marsh and the area burned in 2005. A—dry sand prairie, B—dry-mesic sand prairie, C—mesic sand prairie, D—wet sand prairie, E—sedge meadow (east), F—sedge meadow (west), G—successional lowland, and H—successional upland. Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 43 circular plots were located 6 m from the center point of each plot along cardinal compass direc- tions. In the 0.0001-ha plots, woody seedlings (<50 cm tall) were counted; in the 0.001-ha circular plots small saplings (>50 cm tall and <2.5 cm dbh) were recorded; and in the 0.01-ha circular plots large saplings (2.5–<10.0 cm dbh) were tallied. During the late fall and winter of 2001, these forested areas, including their woody understory, were removed to reestablish prairie vegeta- tion. The bare sand and woody waste were left on the sites and no prairie seed was planted. The resulting lowland and upland successional communities were examined in 2002, 2003, and 2006. Within each community four transects were randomly located. Along each transect, 1m2 plots were located at 1-m intervals alternately along transects (n=100). A random numbers table was used to determine the number of meters (0 to 9) a plot was located from the transect line. Species cover was determined using the Dauben- mire (1959) cover class system as modified by Bailey and Poulton (1968). Importance values were determined by summing relative cover and relative frequency. Aerial photographs from 1939, 1951, 1970, and 1988 were digitized to determine woody encroachment (trees and large shrubs) at the GR- SWA. These aerial photographs were borrowed from the University of Illinois Map Library and scanned with a Microtek ScanMaker. Twenty- one stratified random 5-ha sites, approximately 10.12% of the GRSWA, were interpreted and then digitized using ARC/INFO. The 1939, 1951, and 1970 photographic surveys were all flown in August whereas the 1988 aerial survey was flown in April. RESULTS Dry Sand Prairie: One high-quality dry sand prairie was encountered on the GRSWA (SW1/4 SW1/4 S7 T19N R9E; Fig. 2). This site, approxi- mately 2 ha in size, was located on the ridge and upper slopes of a large stabilized sand dune com- posed of Chelsea fine sand . The dominant grass- es, which did not exceed 1 m in height, were Schizachyrium scoparium, Koeleria macrantha, Dichanthelium villosissimum, and Leptoloma cognatum. Ambrosia psilostachya ranked second in importance, while other common forbs in- cluded Chrysopsis camporum, Solidago nemora- lis, and Coreopsis lanceolata (Table1). Amorpha cansecens, Rosa carolina, and Rhus aromati- ca were the only woody species encountered in the plots . Based on the Sorensen Index of Similarity the dry sand prairie was very simi- lar to the dry mesic sand prairie, but had no species in common with the sedge meadows (Table 2). Within the dry sand prairie, 48 taxa were recorded in the plots, including 4 exotic species, Achillea millefolium being the most important. Average bare ground and litter was 29%, the vegetation being relatively sparse. A total of 94 species were observed in the dry sand prairie for an FQI of 36.16 and a mean CC of 3.73. Dry-mesic Sand Prairie: On the east side of the GRSWA was a dry-mesic sand prairie on Chelsea fine sand. This sand prairie, covering 3 ha, occupied the dune ridge and upper dune slopes (NE1/4 SW1/4 S17 T19N R9E; Fig. 2). The dominant grasses, which were between 0.9 and 1.3 m tall, included Sorghastrum nutans and Schizachyrium scoparium. Other relatively common grasses were shorter and included Dichanthelium villosissimum, D. oligosanthes, D. perlongum, and Leptoloma cognatum (Table 1). Important forbs included Antennaria plantaginifolia, Liatris aspera, Euthamia gymnospermoides, and Euphorbia corollata. Antennaria plantaginifolia com- monly covered small areas in a near monocul- ture. Based on the Sorensen Index of Similar- ity, the dry-mesic and mesic prairies were similar but had only a few species in common with the wet prairies and sedge meadows (Table 2). Within the dry-mesic sand prairie, 37 species were found in the plots, including three exotic species, Rumex acetosella, Poa pratensis, and Achillea millefolium. Vegeta- tion was relatively sparse as indicated by the high values for bare ground and litter (25%). A total of 102 species were observed in the dry-mesic sand prairie resulting in a FQI of 37.77 and a mean CC of 3.74. Mesic Sand Prairie: One high-quality mesic to wet-mesic sand prairie occurred on the GR- SWA (SW1/4 S17 T19N R9E; Fig. 2). This extensive area of approximately 34 ha in size had high species diversity and contained few exotic species. Topographic differences were responsible for the mosaic of sand species that existed here, varying from the dry-mesic sand prairies on the low dune ridges to sand Vol. 39 Art. 244 Illinois Natural History Survey Bulletin Table 1. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species (with IVs >2.0) encountered in late summer of 2006 in a dry sand prairie, a dry-mesic sand prairie, and a mesic sand prairie, Green River State Wildlife Area, Lee County, Illinois. (n = 50) (*exotic species) Dry Sand Prairie Dry-mesic Sand Prairie Mesic Sand Prairie Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV Schizachyrium scoparium 100 26.00 48.7 96 6.32 15.1 2 0.06 0.1 Ambrosia psilostachya 100 10.58 25.2 -- -- -- -- -- -- Amorpha canescens 64 5.91 14.8 -- -- -- -- -- -- Chrysopsis camporum 38 4.61 10.5 -- -- -- -- -- -- Solidago nemoralis 48 3.59 9.9 14 0.17 1.1 10 0.25 0.8 Coreopsis lanceolata 54 3.14 9.7 -- -- -- -- -- -- Cyperus lupulinus 86 0.53 8.7 44 0.27 3.2 -- -- -- Rosa carolina 46 1.75 6.9 28 0.93 3.1 -- -- -- *Achillea millefolium 60 0.45 6.2 22 0.21 1.7 50 0.75 3.6 Koeleria macrantha 46 0.53 5.0 -- -- -- -- -- -- Tephrosia virginiana 14 2.31 4.8 -- -- -- -- -- -- Dichanthelium villosissimum 44 0.47 4.7 88 1.28 7.3 -- -- -- Leptoloma cognatum 42 0.41 4.4 52 1.00 4.7 -- -- -- Liatris aspera 22 0.89 3.4 100 8.80 18.9 -- -- -- Polygala polygama 32 0.16 3.1 100 0.55 7.0 -- -- -- Asclepias verticillata 30 0.15 2.9 4 0.02 0.3 -- -- -- *Poa pratensis 30 0.15 2.9 38 0.19 2.7 46 2.61 4.5 Rhus aromatica 10 1.02 2.5 -- -- -- -- -- -- *Rumex acetosella 24 0.12 2.4 62 0.76 5.0 -- -- -- Dichanthelium oligosanthes 16 0.08 1.6 80 0.75 6.1 -- -- -- Sorghastrum nutans 6 0.03 0.5 98 8.32 18.1 100 28.22 23.7 Antennaria plantaginifolia 2 0.06 0.3 88 16.45 29.2 6 0.08 0.4 Lespedeza capitata 2 0.06 0.3 74 2.34 8.0 4 0.02 0.3 Euphorbia corollata 2 0.01 0.2 96 5.26 13.6 -- -- -- Euthamia gymnospermoides 2 0.01 0.0 196 7.54 16.9 100 7.56 11.0 Carex tonsa -- -- -- 100 1.70 8.7 -- -- -- Rubus flagellaris -- -- -- 56 2.63 7.3 22 2.00 2.6 Dichanthelium perlongum -- -- -- 66 1.42 6.2 -- -- -- Aristida basiramea -- -- -- 62 0.31 4.4 -- -- -- Andropogon gerardii -- -- -- 14 0.85 2.1 70 6.39 8.4 Agrostis gigantea -- -- -- 14 0.07 1.0 54 3.69 5.7 Parthenium integrifolium -- -- -- 8 0.36 1.0 100 34.31 27.5 Viola sagittata -- -- -- 4 0.31 0.8 98 7.05 10.5 Fragaria virginiana -- -- -- -- -- -- 100 16.63 16.6 Liatris pycnostachya -- -- -- -- -- -- 98 13.04 14.2 Dichanthelium acuminatum -- -- -- -- -- -- 98 8.50 11.4 Desmodium illinoense -- -- -- -- -- -- 94 8.62 11.2 Rudbeckia subtomentosa -- -- -- -- -- -- 68 6.47 8.3 Antennaria neglecta -- -- -- -- -- -- 44 6.59 6.9 Panicum virgatum -- -- -- -- -- -- 46 3.00 4.8 Acalypha gracilens -- -- -- -- -- -- 64 0.61 4.4 Polygala sanguinea -- -- -- -- -- -- 60 0.30 4.0 Hypericum punctatum -- -- -- -- -- -- 50 0.55 3.4 Solidago canadensis -- -- -- -- -- -- 32 1.38 2.9 Others -- 2.76 20.4 -- 0.55 6.5 -- 3.05 12.8 Totals 65.77 200.0 69.36 200.0 161.73 200.0 Bare ground and litter 28.71 25.35 13.03 Table 1. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species (with IVs >2.0) encountered in late summer of 2006 in a dry sand prairie, a dry-mesic sand prairie, and a mesic sand prai- rie, Green River State Wildlife Area, Lee County, Illinois. (n = 50) (*exotic species) Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 45 Table 2. Similarity Index of the sand prairies and sedge meadows at the GRSWA. Communities Dry Sand Prairie Dry-mesic Sand Prairie Mesic Sand Prairie Wet Sand Prairie Sedge Meadow (1) Dry-mesic Sand Prairie 58.82 Mesic Sand Prairie 26.09 49.38 Wet Sand Prairie 10.34 11.43 25.00 Sedge Meadow (1) 00.00 00.00 00.00 27.96 Sedge Meadow (2) 00.00 3.03 5.49 22.68 18.52 ponds in the small depressions. Mesic sand prairie vegetation occurred on the slopes of the dunes where the soils were comprised of Dakota sandy loam. In contrast, the wet-mesic prairie was on the lower ground between the dunes on Hoopeston fine sandy loam. Sorghas- trum nutans and Andropogon gerardii were the dominant tall grasses, commonly being more than 1.6 m tall. Other common grasses included Dichanthelium acuminatum, Agrostis gigantea, and Panicum virgatum (Table 1). The important native forbs included Parthe- nium integrifolium, Fragaria virginiana, Liatris pycnostachya, Desmodium illinoense, and Euthamia gymnospermoides (Table 1). Based on the Sorensen Index of Similarity, the mesic sand prairie was similar to the dry mesic sand prairies, and has very low similarity to the wet sand prairie and sedge meadows (Table 2). A total of 44 taxa were encountered in the plots, including 3 exotic species. Bare ground and lit- ter averaged 13%. A total of 124 species were observed in the mesic prairie resulting in a FQI of 45.21 and a mean CC of 4.06. Wet Sand Prairie: A 5-ha wet sand prairie was located along the western and northern edges of a sedge meadow at the southeastern part of the GRSWA (NE1/4 SW1/4 S17 T19N R9E; Fig. 2). The vegetation of this prairie was transition- al between the sedge meadow and wet-mesic to mesic sand prairie to the north and west. Here, changes in species composition occurred depending upon slight differences in elevation. Spartina pectinatus was the dominant grass, while Carex haydenii was the most important sedge. Common forbs included Helianthus grosseserratus, Solidago canadensis, Onoclea sensibils, Galium obtusum, Hypericum spha- erocarpum, and Silphium integrifolium all with IVs of 8.0 or higher (Table 3). Based on the Sorensen Index of Similarity, the wet sand prai- rie was similar to the mesic sand prairies and the sedge meadows, with low similarity to the drier sand communities (Table 2). Within the wet prairie 68 taxa were encountered, including three exotic species, Poa pratensis being the most important. Bare ground and litter aver- aged less than 2%. A total of 102 species were observed in the wet sand prairie for an FQI of 39.11 and a mean CC of 3.87. Sedge Meadows: Hummocks were present throughout the sedge meadows, their height dependent on the distance from the sedge meadow center, i.e., smaller hummocks near the edge, larger and taller hummocks near the center. One small sedge meadow, covering less than 0.5 ha, occurred in a shallow depression near the southeast corner of GRSWA (NE1/4 SW1/4 S17 T19N R9E; Fig. 2) (sedge meadow East). Bolboschoenus fluvatilis was the most important species, followed by Carex haydenii. The common species recorded for this sedge meadow included Thelypteris palustris, Onoclea sensibilis, and Aster praealtus. At the south edge of this sedge meadow was a depres- sion that likely represents an old sand pond that became partially filled and no longer holds water year around. Bolboschoenus fluviatalis dominated this depression, with Persicaria amphibium also common. A total of 44 species were observed in this sedge meadow, yielding a FQI of 30.30 and a mean CC of 4.57. A 1.5-ha sedge meadow was located at the southeast corner of the marsh (SE1/4 NE1/4 S13 T19N R8E; Fig. 2) (sedge meadow West). In 2002 this sedge meadow was dominated by Table 2. Similarity Index of the sand prairies and sedge meadows at the GRSWA. Vol. 39 Art. 246 Illinois Natural History Survey Bulletin Carex haydenii and Calamagrostis canadensis, with Persicaria coccinea also common (Table 4). Twenty-nine taxa including three exotic species were encountered in the plots: Mentha arvensis was extremely common, followed by Chenopodium album and Persicaria vulgaris. Though burned in 2005, no peat fires occurred here and the area was not subjected to disking. The three most important species in 2005 main- tained their dominance during 2006 and 2007. Eleven additional species were found in the Table 3. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species (with IVs >2.0) encountered in late summer of 2006 in a wet sand prairie and an adjacent sedge meadow (sedge meadow East), Green River State Wildlife Area, Lee County, Illinois. (n = 50) (*exotic species) Wet Sand Prairie Sedge Meadow East Species Freq. % Mean Cover IV Freq. % Mean Cover IV Spartina pectinata 50 23.75 18.8 -- -- -- Helianthus grosseserratus 96 13.57 14.9 -- -- -- Solidago canadensis 72 15.03 14.3 -- -- -- Carex haydenii 100 8.23 11.6 52 36.21 38.9 Onoclea sensibilis 66 8.46 9.6 66 7.01 16.5 Galium obtusum 82 4.95 8.3 2 0.01 0.3 Hypericum sphaerocarpum 78 5.15 8.3 -- -- -- Silphium integrifolium 48 7.59 8.0 -- -- -- Viola pratincola 64 5.90 7.9 -- -- -- Stachys pilosa 92 2.62 7.4 -- -- -- Thalictrum dasycarpum 52 6.12 7.2 -- -- -- Euthamia gymnospermoides 42 5.10 5.9 -- -- -- Rudbeckia subtomentosa 38 5.19 5.8 -- -- -- Solidago gigantea 56 2.96 5.4 -- -- -- Aster praealtus 44 3.81 5.2 48 5.71 12.6 Pycnanthemum virginianum 42 3.46 4.9 -- -- -- Cirsium discolor 38 3.20 4.5 -- -- -- Comandra umbellata 26 3.90 4.2 -- -- -- Calystegia sepium 38 2.29 3.9 -- -- -- Thelypteris palustris 24 3.31 3.7 50 13.85 19.8 Calamagrostis canadensis 40 1.71 3.6 -- -- -- Rubus pensilvanicus 30 1.62 3.0 -- -- -- Campanula aparinoides 44 0.32 2.9 16 0.08 2.7 Muhlenbergia mexicana 32 1.24 2.8 6 0.08 1.1 Asclepias syriaca 22 1.14 2.1 -- -- -- Persicaria amphibium 24 0.46 1.8 50 4.95 12.3 Bolboschoenus fluviatilis 10 0.44 0.9 50 42.51 44.3 Lycopus uniflorus 10 0.15 0.7 36 0.38 6.1 Verbena hastata 2 0.06 0.1 42 0.66 7.4 Boehmeria cylindrica 2 0.01 0.1 60 2.59 12.0 Scutellaria galericulata -- -- -- 26 0.13 4.3 *Solanum dulcamara -- -- -- 18 0.82 3.6 Triadenum fraseri -- -- -- 18 .078 3.5 *Phalaris arundinacea -- -- -- 14 1.23 3.3 Bidens coronata -- -- -- 14 0.22 2.5 Caltha palustris -- -- -- 12 0.26 2.1 Others -- 11.40 22.2 -- 1.06 6.7 Totals 153.14 200.0 118.54 200.0 Bare ground and litter 1.50 1.88 plots in 2006. By 2007 most of these species were lost or greatly reduced in abundance, and the original dominants of 2002 had regained much of their previous importance. By 2007 two native forbs, Teucrium canadense and As- ter praealtus, had become more obvious (Table 4). In 2002, a total of 42 species were observed in this sedge meadow for an FQI of 21.49 and a mean CC of 3.31. Table 3. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species (with IVs >2.0) encountered in late summer of 2006 in a wet sand prairie and an adja- cent sedge meadow (sedge meadow East), Green River State Wildlife Area, Lee County, Illinois. (n = 50) (*exotic species) Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 47 Marsh: Located along the western edge of the GRSWA, the marsh was divided into five vegetation zones (W1/2 S13 T19N R8E; Fig. 2). Within this 40-ha marsh/sedge meadow complex the vegetation zones were mostly de- pendent on slight differences in elevation, soils, and past disturbance, particularly drainage attempts and fire frequency, intensity, and time of year. The transitions between the various vegetation zones were abrupt with the edges of the zones being very distinct. Of the 36 species encountered, including several conservative species, only 5 were exotics. The marsh FQI was 18.48 and the mean CC was 3.08. Much of this marsh area was burned in the fall of 2005. Phalaris Vegetation Zone: The exotic Phalaris arundinacea was the dominant species in shallow areas throughout the marsh where water level fluctuations were pronounced (Ta- ble 5). This disturbance community occurred in areas where water levels were usually low and flooding was of short duration. This zone was found throughout nearly all of the exten- sive wetlands at the GRSWA and accounted for nearly half of the marsh area. When surveyed in 2002, Phalaris arundinacea dominated, Per- sicaria coccinea was second, and six other spe- cies were encountered. In 2006, after the 2005 fire, P. arundinacea continued to dominate. Many other species were also present in 2006, but by 2007 many had disappeared (Table 5). Most notable was Ambrosia artemisiifolia, which in 2006 was second in imnportance, but was not found in the plots in 2007. Salix interior thickets were common at the edge of the marsh as narrow bands at the base of the stabilized dunes. When surveyed in 2002, Phalaris arundinacea dominated the ground layer beneath these willow thick- ets; Persicaria punctatum was also common, whereas seven other species were occasionally encountered (Table 6). After the 2005 fire, P. arundinacea still dominated; Urtica gracilis was second in importance in 2006 but dropped to third by 2007. Five taxa not found in 2002 were encountered in 2006, and the number of new species had increased to 14 by 2007. An extensive Phalaris arundinacea popula- tion occurred in a shallow depression near the middle of the GRSWA and close to the of- fice building (SW1/4 NE1/4 S18 T19N R9E). During the 2005 fire, this entire area burned and extensive peat fires destroyed much of the peat; the depression was flooded and disked in efforts to control the fires. Phalaris arun- dinacea was not recorded in any of the plots when the site was surveyed in 2006. Thirteen native species were present, although the exotic Circium arvense was the dominant taxon (Table 7). Other relatively important species included the native taxa Oenothera biennis, Verbena hastata, and Persicaria punctata along with the exotic Chenopodium album. By 2007 P. arundi- nacea had returned, Cirsium arvense had nearly disappeared and though many native weedy species had invaded, extensive areas of bare ground were present (Table 7). Typha/Persicaria Vegetation Zone: Scattered throughout the marsh in 2002 were extensive areas of Typha latifolia (Table 8). Persicaria cooccinea and Carex lacustris were common among the cattails. Many other species were occasionally encountered, although none were very important, as indicated by low mean cov- er. Typha latifolia nearly disappeared follow- ing the fire, before increasing in importance in 2007 (Table 8). Phalaris arundinacea increased between 2005 and 2006, and by 2007 was the dominant species present. Fourteen additional species were recorded in these plots in 2006, whereas many had disappeared by 2007. One extensive Typha latifolia population of 16 ha in size occurred next to the road at the western edge of the marsh, separated from the rest of the marsh by a narrow sand ridge. Dur- ing the 2005 fire, much of this area burned and the fire destroyed extensive areas of peat, the fires smoldering for a few days. The depression was intentionally flooded and disked. Though the dominant species before the 2005 fire, T. latifolia was uncommon in 2006, but increased significantly in 2007 (Table 9). Phalaris arun- dinacea, which was rarely encountered before the 2005 fire, was the dominant species in 2006 and 2007. Bolboschoenus fluviatilis Vegetation Zone: Bolboschoenus fluviatilis was the dominant species in an area of about 1.2 ha (Table 10). Persicaria coccinea, Sparganium eurycarpum, and Urtica gracilis were common under the river bulrush. Only five species were found in the plots and no exotic species were encoun- tered in 2002 (Table 10). After the 2005 fire, B. fluviatilis initially decreased and then increased in importance. Thirteen additional species were recorded in these plots in 2006, although many had disappeared by 2007. By 2007, Persicaria coccinea had recovered, Sparganium eury- Vol. 39 Art. 248 Illinois Natural History Survey Bulletin Table 4. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a sedge meadow (sedge meadow West) at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Summer 2002 Summer 2006 Summer 2007 Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV Carex haydenii 100 30.93 43.7 100 43.09 38.9 96 43.85 43.9 Calamagrostis canadensis 100 29.88 42.7 96 29.32 29.3 100 52.80 50.4 Persicaria coccinea 52 17.27 24.0 34 9.01 9.4 56 16.92 19.8 *Mentha arvensis 72 5.18 15.0 38 1.08 4.5 20 1.12 3.8 Eupatoriadelphus maculatus 56 7.06 14.6 28 1.56 3.9 10 0.73 2.1 Persicaria punctata 72 1.40 11.3 64 1.11 7.0 44 0.62 7.2 Lycopus uniflorus 58 2.31 10.3 62 1.36 7.0 22 0.75 3.9 Verbena hastata 28 2.04 5.9 2 0.01 0.2 16 0.23 2.7 Scutellaria galericulata 24 0.76 4.1 10 0.10 1.1 10 0.15 1.6 Helianthus grosseserratus 20 1.27 4.0 84 17.40 20.0 16 0.18 2.6 Teucrium canadense 22 0.60 3.7 82 6.15 12.3 42 0.95 7.1 Lycopus americanus 16 0.67 2.8 18 0.44 2.1 8 0.48 1.5 Polygonum ramosissimum 14 0.46 2.5 40 2.20 5.5 20 0.10 3.2 Aster puniceus 12 0.60 2.3 36 2.47 5.3 14 0.56 2.6 Ambrosia artemisiifolia 10 0.49 1.9 50 11.47 12.6 10 0.10 1.6 Stachys pilosa 8 0.48 1.6 28 4.62 5.9 -- -- -- Rumex orbiculatus 8 0.43 1.5 4 0.02 0.4 2 0.30 0.5 Asclepias incarnata 8 0.14 1.2 -- -- -- 2 0.01 0.3 Galium obtusum 6 0.42 1.2 4 0.60 0.8 2 0.01 0.3 Aster praealtus 4 0.36 0.9 40 5.86 7.9 86 26.43 30.8 Epilobium coloratum 4 0.36 0.9 -- -- -- -- -- -- Solidago gigantea 4 0.31 0.9 50 6.96 9.6 8 0.24 1.4 Cardamine pensylvanica 6 0.03 0.8 2 0.01 0.2 8 0.04 1.2 Acalypha rhomboidea 2 0.06 0.4 2 0.01 0.2 2 0.01 0.3 Eleocharis verrucosa 2 0.06 0.4 -- -- -- -- -- -- Geum laciniatum 2 0.06 0.4 -- -- -- -- -- -- Lathyrus palustris 2 0.06 0.4 -- -- -- 12 1.03 2.7 *Chenopodium album 2 0.01 0.3 44 1.21 5.1 -- -- -- *Persicaria vulgaris 2 0.01 0.3 -- -- -- -- -- -- *Potentilla norvegica -- -- -- 38 0.24 4.0 4 0.02 0.6 Cirsium discolor -- -- -- 20 0.35 2.2 2 0.01 0.3 Solidago canadensis -- -- -- 4 1.50 1.4 4 0.07 0.6 Lactuca canadensis -- -- -- 10 0.10 1.1 -- -- -- *Cirsium arvense -- -- -- 4 0.12 0.5 -- -- -- Persicaria pensylvanica -- -- -- 4 0.02 0.4 -- -- -- *Trifolium repens -- -- -- 4 0.02 0.4 -- -- -- Hackelia virginiana -- -- -- 2 0.06 0.2 -- -- -- Helenium autumnale -- -- -- 2 0.06 0.2 -- -- -- Solanum ptychanthum -- -- -- 2 0.01 0.2 -- -- -- Typha latifolia -- -- -- 2 0.01 0.2 16 0.96 3.1 *Phalaris arundinacea -- -- -- -- -- -- 12 1.77 3.0 Eupatorium perfoliatum -- -- -- -- -- -- 2 0.01 0.3 Iris shrevei -- -- -- -- -- -- 2 0.01 0.3 Lysimachia thrysiflora -- -- -- -- -- -- 2 0.06 0.3 Totals 103.71 200.0 148.55 200.0 150.52 200.0 Bare ground and litter 1.20 3.65 2.13 Table 4. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a sedge meadow (sedge meadow West) at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 49 carpum was still recovering, whereas Urtica gracilis was not recorded. Sparganium eurycarpum Vegetation Zone: A few small areas of ≤ 0.5 ha were dominated by Sparganium euryocarpum (Table 11). Persi- caria coccinea was also important followed by Urtica gracilis. Only eight species were found in the plots and the exotic Phalaris arundina- cea was rarely encountered. After the 2005 fire, S. eurycarpum was absent from the plots and by 2007 was still uncommon. In contrast, Per- sicaria coccinea increased in important in 2006 and again in 2007. Thirteen additional species were recorded in these plots in 2006, whereas some were absent in 2007. Carex lacustris/Persicaria coccinea Vegeta- tion Zone: Located next to the sedge meadow in the southeastern part of the marsh, this zone covered approximately 5 to 6 ha . The dominant species, Carex lacustris, Persicaria coccinea, and Calamagrostis canadensis, far exceed the importance of the other species present (Table 12). Thirteen species were encountered in the plots with more than half having IVs of less than 1.5. Though burned in 2005, no peat fires occurred and the area was not subjected to disking. During the 2006 and 2007 surveys, the three dominant species maintained their importance. Seventeen additional species were found in the plots in 2006, including the native Ambrosia artemisiifolia and exotic Chenopodi- um album. By 2007 most of these species were absent or greatly reduced in abundance, and the original dominants of 2002 had regained much of their previous importance. By 2007 two native prairie forbs, Teucrium canadense and Aster praealtus, became much more abundant (Table 12). Sand Pond: Scattered through the lowlands of the GRSWA were a few small sand ponds, none more than 55 m across. The vegetation sur- rounding these ponds varied extensively. Most ponds were located where Phalaris arundi- nacea dominated the pond margins with few other species being encountered. Around a few Table 5. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Phalaris arundinacea vegetation zone that is not shaded in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Summer 2002 Summer 2006 Summer 2007 Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV *Phalaris arundinacea 100 79.05 130.1 100 84.55 117.1 100 83.30 142.4 Persicaria coccinea 80 8.17 44.3 66 7.45 28.5 60 7.27 40.2 Leersia oryzoides 20 1.94 10.9 -- -- -- -- -- -- Iris shrevei 16 1.63 8.9 4 0.07 1.4 8 1.41 5.8 Typha latifolia 4 0.12 1.9 -- -- -- -- -- -- Hibiscus laevis 2 0.75 1.7 -- -- -- -- -- -- Sium suave 2 0.30 1.2 -- -- -- -- -- -- *Cirsium arvense 2 0.06 1.0 4 0.02 1.3 -- -- -- Ambrosia artemisiifolia -- -- -- 84 4.99 31.8 -- -- -- Rubus pensilvanicus -- -- -- 12 1.56 5.4 10 1.95 7.5 Scirpus cyperinus -- -- -- 6 0.08 2.0 -- -- -- Persicaria punctata -- -- -- 6 0.03 1.9 2 0.01 1.1 *Sida spinosa -- -- -- 6 0.03 1.9 -- -- -- Stachys pilosa -- -- -- 4 0.07 1.4 -- -- -- Teucrium canadense -- -- -- 4 0.12 1.4 -- -- -- Verbena hastata -- -- -- 4 0.02 1.3 -- -- -- Calamgrostis canadensis -- -- -- 2 0.30 0.9 2 0.75 1.9 Ambrosia trifida -- -- -- 2 0.06 0.7 -- -- -- Carex lacustris -- -- -- 2 0.01 0.6 2 0.01 1.1 Hackelia virginiana -- -- -- 2 0.01 0.6 -- -- -- Solanum ptychanthum -- -- -- 2 0.01 0.6 -- -- -- *Verbascum thapsus -- -- -- 2 0.01 0.6 -- -- -- Vitis riparia -- -- -- 2 0.01 0.6 -- -- -- Totals 92.02 200.0 99.40 200.0 94.70 200.0 Bare ground and litter 10.61 5.76 6.08 Table 5. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Phalaris arundinacea vegetation zone that is not shaded in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Vol. 39 Art. 250 Illinois Natural History Survey Bulletin ponds, however, wet to wet-mesic sand prairie vegetation dominated depending on the steep- ness of the shoreline. No high-quality sand ponds were encountered during this study. Sand Forest: Both lowland and upland forests were located at GRSWA (Fig. 2). The lowland forests were dominated by Acer saccharinum with a few subdominant species including Prunus serotina, Populus deltoides, Juglans nigra, Acer negundo, Salix nigra, and Fraxinus pennsylvanica (Sites 1, 2, 3, and 4, Table 13). In these forests Acer saccharinum was consis- tently of highest importance, highest density, and of relatively large size. In contrast, the upland forests where commonly dominated by Prunus serotina along with the exotic spe- cies Morus alba or Robinia pseudoacacia and some of the lowland forest species (Sites 5 and 6, Table 13). In both forest types the woody understory was dense, with many native and exotic trees and shrubs common. Overall, woody seedling densities averaged between 6,000 and 16,000 stems/ha, small saplings averaged between 3,200 and 6,850 stems/ha, while large saplings were not common with an average between 0 and 740 stems/ha. The most abundant understory shrubs were mostly exotic species with Elaeagnus umbellata, Lonicera maackii, Lonicera x bella, Rhamnus cathartica, and Rosa multiflora common. The ground layer in these six forest sites was similar. In addition to the numerous woody tree seedlings and shrub in the ground layer, many herbaceous species were common. Generally na- tive herbs dominated, with Ageratina altissima, Antenoron virginianum, Boehmeria cylindrica, Cryptotaenia canadensis, Geum canadense, Osmorhiza sp., Phytolacca americana, Solidago canadensis, and S. gigantea being the most com- mon taxa. A few exotic herbs such as Alliaria petiolata, Bromus inermis, Fallopia convolvulus, Table 6. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Phalaris arundinacea vegetation zone community that is shaded under a thicket of Salix interior in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50). (*exotic species) Summer 2002 Summer 2006 Summer 2007 Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV *Phalaris arundinacea 100 59.10 146.3 100 73.77 136.9 100 48.05 97.2 Persicaria punctata 48 1.24 26.5 14 1.38 9.3 50 6.56 23.4 Urtica gracilis 14 0.12 7.3 38 7.71 29.6 42 3.24 16.4 Persicaria coccinea 10 0.78 6.4 -- -- -- 2 0.30 1.0 Carex lacustris 10 0.54 6.0 -- -- -- -- -- -- Scutellaria lateriflora 6 0.13 3.3 -- -- -- -- -- -- Pilea pumila 4 0.02 2.1 -- -- -- 24 2.51 10.3 Vitis riparia 2 0.06 1.1 -- -- -- 2 0.06 0.7 Phytolacca americana 2 0.01 1.0 4 1.05 3.4 6 0.08 1.8 Fallopia scandens -- -- -- 16 6.05 15.6 12 2.01 6.2 Persicaria pensylvanica -- -- -- 2 0.30 1.4 40 3.07 15.4 Rubus occidentalis -- -- -- 2 0.30 1.4 -- -- -- *Silene pratensis -- -- -- 2 0.06 1.2 -- -- -- Solanum ptychanthum -- -- -- 2 0.06 1.2 6 0.03 1.8 Lemna minor -- -- -- -- -- -- 32 1.34 10.9 Salix nigra -- -- -- -- -- -- 10 0.34 3.3 *Alliaria petiolata -- -- -- -- -- -- 8 0.67 3.2 Boehmeria cylindrica -- -- -- -- -- -- 8 0.14 2.4 Cuscuta gronovii -- -- -- -- -- -- 4 0.07 1.1 Rorippa palustris -- -- -- -- -- -- 4 0.07 1.1 Aster puniceus -- -- -- -- -- -- 2 0.30 1.0 Typha latifolia -- -- -- -- -- -- 2 0.30 1.0 Cirsium discolor -- -- -- -- -- -- 2 0.01 0.6 Geum canadense -- -- -- -- -- -- 2 0.01 0.6 *Persicaria vulgaris -- -- -- -- -- -- 2 0.01 0.6 Totals 62.00 200.0 90.68 200.0 69.17 200.0 Bare ground and litter 34.02 4.42 34.20 Table 6. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Phalaris arundinacea vegetation zone community that is shaded under a thicket of Salix interior in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50). (*exotic species) Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 51 and Phalaris arundinacea sometimes domi- nated. Woody encroachment at the GRSWA had increased dramatically, based on the analysis of aerial photographs. In 1939, one year after the initial purchase of the land for the GRSWA, approximately 47.5 ha (4.6% cover) were covered by trees and large shrubs. The extent of the forested areas had increased to 72.2 ha (7% cover) by 1951, 184.9 ha (17.8% cover) in 1970, and 294.6 ha (29.4% cover) in 1988. Woody encroachment was most obvious along many of the original hedge rows and where pine plantations were introduced soon after the site was purchased. In 2001 most of the forests at the GRSWA were clear-cut. Two of these resulting succes- sional areas, a lowland and an upland site, were surveyed in 2002, 2003, and 2006. Of 47 taxa recorded in 2002, Phalaris arundinacea and Persicaria pensylvanica dominated the lowland site (Table 14). In 2003, P. arundinacea contin- ued to dominate with Persicaria pensylvanica, Conyza canadensis, Potentilla norvegica, and Populus deltoids seedlings important. Phalaris arundinacea dominated during the 2006 survey, whereas Solidago canadensis, Persicaria pen- sylvanica, Lactuca serriola, and Chenopodium album were among the most important of 58 species encountered (Table 14). Throughout the survey, P. arundinacea and Persicaria pen- sylvanica remained dominant members of the lowland community. Overall, 17 species were recorded in all 3 years of the study, with 23 taxa restricted to 2006, 20 found only in 2003, and 15 restricted to 2002; 28 exotic species were recorded in the lowland plots . Table 7. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2006 and 2007 in a marsh that had been dominated by Phalaris arundinacea prior to a fire in late 2005, Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Summer 2006 Summer 2007 Species Freq. % Mean Cover IV Freq. % Mean Cover IV *Cirsium arvense 100 63.00 123.8 2 0.01 0.9 Oenothera biennis 20 3.45 13.5 -- -- -- *Chenopodium album 20 3.00 12.9 -- -- -- Verbena hastata 18 2.41 11.2 -- -- -- Persicaria punctata 16 2.85 10.8 78 11.93 91.0 Amaranthus tuberculatus 12 2.70 8.8 -- -- -- Cycloloma atriplicifolium 8 0.96 4.9 -- -- -- Calamagrostis canadensis 6 0.90 3.9 14 4.74 28.8 Solanum ptychanthum 6 0.03 2.8 -- -- -- Ambrosia artemisiifolia 2 0.30 1.3 -- -- -- Aster praealtus 2 0.30 1.3 22 0.50 12.0 Euthamia graminifolia 2 0.30 1.3 -- -- -- Persicaria pensylvanica 2 0.30 1.3 40 1.33 23.8 Solidago canadensis 2 0.30 1.3 -- -- -- Carex haydenii 2 0.06 0.9 -- -- -- *Phalaris arundinacea -- -- -- 8 1.33 9.9 Persicaria lapathifolia -- -- -- 6 0.18 3.5 Typha latifolia -- -- -- 14 0.17 6.9 Salix nigra -- -- -- 12 0.06 5.5 Carex lacustris -- -- -- 6 0.42 4.6 *Mentha arvensis -- -- -- 6 0.03 2.7 Persicaria amphibium -- -- -- 4 0.07 2.0 Cardamine pensylvanica -- -- -- 4 0.02 1.8 *Persicaria vulgaris -- -- -- 4 0.02 1.8 Salix interior -- -- -- 4 0.02 1.8 *Setaria faberi -- -- -- 2 0.06 1.2 Populus deltoides -- -- -- 2 0.01 0.9 *Potentilla norvegica -- -- -- 2 0.01 0.9 Totals 80.86 200.0 20.91 200.0 Bare ground and litter 22.12 71.52 Table 7. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2006 and 2007 in a marsh that had been dominated by Phalaris arundinacea prior to a fire in late 2005, Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Vol. 39 Art. 252 Illinois Natural History Survey Bulletin In 2002 Phytolacca americana dominated the upland site, with Solanum ptychanthum, Che- nopodium album, Lonicera maackii, and Cype- rus schweinitzii following in importance (Table 15). By 2003 Conyza canadensis dominated, followed by Lonicera maackii, Verbascum thapsus, and Cyperus lupulinus. In 2006 Rubus pensilvanicus, Verbascum thapsus, Chenopo- dium album, and Lonicera maackii were the important taxa. The number of taxa recorded in the plots varied from 41 to 48, including 21 exotic species. DISCUSSION Exotic Species: The sand prairie communities at the GRSWA had high species richness, many prairie conservative species, and few exotic taxa. Exotic species were usually present in low numbers, occurred in restricted areas, and were not major community components. Only three exotic species were consistently encountered in the plots of the upland sand prairies. These species, Achillea millefolium, Rumex acetosella and Poa pratensis, were mostly localized, and though sometimes recorded in high frequencies, they had low densities. In the wet sand prairie Table 8. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Typha latifolia vegetation zone in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Summer 2002 Summer 2006 Summer 2007 Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV Typha latifolia 100 56.15 86.7 6 0.08 0.9 42 4.33 16.1 Persicaria coccinea 88 10.99 32.0 86 8.26 18.9 92 16.36 42.3 Carex lacustris 44 15.68 27.8 44 7.67 12.4 46 14.75 27.6 Rorippa palustris 44 1.06 10.9 -- -- -- -- -- -- *Phalaris arundinacea 34 1.82 9.6 92 80.11 77.8 94 62.07 88.4 *Potentilla norvegica 32 0.16 7.2 28 0.29 4.2 -- -- -- Urtica gracilis 32 0.16 7.2 26 1.69 5.1 -- -- -- Cardamine pensylvanica 22 0.16 5.1 14 0.12 2.1 -- -- -- Amaranthus hybridus 16 0.08 3.6 2 0.01 0.3 -- -- -- *Mentha arvensis 14 0.12 3.3 62 4.06 12.1 4 0.02 1.0 Sparganium eurycarpum 12 0.16 2.8 -- -- -- -- -- -- Solanum ptycanthum 6 0.03 1.3 6 0.3 0.8 -- -- -- *Persicaria vulgaris 4 0.02 0.9 4 0.07 0.7 2 0.06 0.7 Celtis occidentalis 2 0.01 0.4 -- -- -- -- -- -- Erechtites hieracifolia 2 0.01 0.4 -- -- -- -- -- -- Phytolacca americana 2 0.01 0.4 -- -- -- -- -- -- Persicaria punctata 2 0.01 0.4 80 2.16 13.0 28 0.73 8.6 *Chenopodium album -- -- -- 78 2.54 13.2 -- -- -- Ambrosia artemisiifolia -- -- -- 48 6.03 11.7 -- -- -- Aster praealtus -- -- -- 28 5.28 8.3 6 0.08 1.8 *Cirsium arvense -- -- -- 36 1.60 6.4 -- -- -- Persicaria pensylvanica -- -- -- 30 2.20 6.1 16 0.62 5.1 Cirsium discolor -- -- -- 8 0.33 1.4 -- -- -- Hackelia virginiana -- -- -- 6 0.37 1.1 18 1.26 6.4 Bolboschoenus fluviatilis -- -- -- 4 0.12 0.7 -- -- -- Cuscuta gronovii -- -- -- 4 0.12 0.7 -- -- -- Parietaria pensylvanica -- -- -- 4 0.12 0.7 -- -- -- Solidago gigantea -- -- -- 2 0.30 0.5 -- -- -- Alliaria petiolata -- -- -- 2 0.01 0.3 -- -- -- Solidago canadensis -- -- -- 2 0.06 0.3 -- -- -- Stachys pilosa -- -- -- 2 0.01 0.3 -- -- -- Cicuta maculata -- -- -- -- -- -- 2 0.06 0.7 Persicaria lapathifolia -- -- -- -- -- -- 2 0.06 0.7 Sium suave -- -- -- -- -- -- 2 0.01 0.6 Totals 86.63 200.0 123.64 200.0 100.41 200.0 Bare ground and litter 11.26 1.49 13.37 Table 8. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Typha latifolia vegetation zone in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 53 Table 9. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2006 and 2007 in a marsh area that had been dominated by Typha latifolia prior to a fire in late 2005, Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Summer 2006 Summer 2007 Species Freq. % Mean Cover IV Freq. % Mean Cover IV *Phalaris arundinacea 100 80.25 132.5 92 18.27 65.5 Persicaria pensylvanica 40 7.31 26.8 32 0.78 9.8 Persicaria punctata 38 3.78 22.1 76 4.66 29.8 *Cirsium arvense 8 0.96 4.8 -- -- -- Ambrosia artemisiifolia 8 0.72 4.6 -- -- -- Typha latifolia 8 0.72 4.6 58 11.64 41.6 Cuscuta gronvii 4 0.36 2.3 -- -- -- Persicaria lapathifolia 4 0.36 2.3 8 0.04 2.1 Bolboschoenus fluviatilis -- -- -- 24 5.48 18.7 Lemna minor -- -- -- 60 0.30 15.7 Persicaria amphibium -- -- -- 40 0.49 11.1 Typha angustifolia -- -- -- 4 1.05 3.5 Schoenoplectus tabernaemontani -- -- -- 2 0.30 1.2 Cardamine pensylvanica -- -- -- 2 0.01 0.5 *Mentha arvensis -- -- -- 2 0.01 0.5 Totals 94.46 200.0 43.03 200.0 Bare ground and litter 6.97 47.55 Table 9. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2006 and 2007 in a marsh area that had been dominated by Typha latifolia prior to a fire in late 2005, Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Table 10. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Bolboschoenus fluviatilis vegetation zone in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Summer 2002 Summer 2006 Summer 2007 Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV Bolboschoenus fluviatilis 100 69.15 109.7 6 0.42 1.5 100 43.95 68.0 Persicaria coccinea 98 14.91 47.0 68 12.85 24.6 98 26.40 50.0 Sparganium eurycarpum 62 2.18 21.4 -- -- -- 26 1.11 7.4 Urtica gracilis 66 1.08 21.3 42 17.02 23.4 -- -- -- Rorippa palustris 2 0.01 0.6 4 0.02 0.8 -- -- -- *Persicaria vulgaris -- -- -- 68 29.04 39.3 2 0.01 0.5 *Chenopodium album -- -- -- 90 5.25 21.8 -- -- -- Persicaria pensylvanica -- -- -- 34 13.86 19.0 70 4.01 21.0 Cuscuta gronovii -- -- -- 62 6.27 17.4 -- -- -- Persicaria punctata -- -- -- 60 6.04 16.9 92 18.76 40.9 *Mentha arvensis -- -- -- 40 9.91 16.6 -- -- -- Persicaria lapathifolia -- -- -- 12 4.41 6.3 -- -- -- Ambrosia artemisiifolia -- -- -- 18 2.70 5.9 -- -- -- *Phalaris arundinacea -- -- -- 10 1.23 3.0 14 6.30 9.7 Amaranthus tuberculatus -- -- -- 6 0.42 1.5 -- -- -- Erechtites hieracifolia -- -- -- 4 0.12 0.8 -- -- -- Aster praealtus -- -- -- 2 0.30 0.7 -- -- -- Cirsium discolor -- -- -- 2 0.06 0.5 -- -- -- Cicuta maculata -- -- -- -- -- -- 2 0.01 0.5 Teucrium canadense -- -- -- -- -- -- 8 0.14 2.0 Totals 87.33 200.0 109.92 200.0 100.69 200.0 Bare ground and litter 11.24 6.60 10.10 Table 10. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Bolboschoenus fluviatilis vegetation zone in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Vol. 39 Art. 254 Illinois Natural History Survey Bulletin the exotic species included Poa pratensis, Lac- tuca serriola, and Rumex crispus, all with very low numbers. In the sedge meadows four exotic species were recorded with Mentha arvensis being the most common. Phalaris arundinacea was the dominant species throughout most of the GRSWA lowlands, particularly the marsh. The abundance of Phalaris arundinacea at GRSWA is an indication of past disturbances, particularly the fluctuation of water levels due to attempts to drain these lowlands. Water table fluctuations resulting from large amounts of ground water being removed for irrigation has exacerbated the problem. The exotic species Morus alba and Robinia pseudoacacia dominated the upland sand for- ests at GRSWA. These disturbed, poor-quality forests had become established due to the lack of fire. Associated shrubs on these wooded sites included the exotics Elaeagnus umbellata, Lonicera maackii, L. x bella, Rhamnus cathar- tica, and Rosa multiflora, which in many areas created impenetrable thickets. When these for- ested areas were clear-cut in 2001, no slash was left on the ground, and the woody understory was removed. All that was left were stumps that were cut very close to the ground, along with mostly bare sand and some areas covered with a layer of litter. A majority of the species colonizing these areas were exotic and native weedy species. Endangered Species: Few endangered and threatened species were encountered in GR- SWA, probably the result of poor management prior to 1993. Botrychium matricariifolium was the only endangered species found at the GRSWA, occurring at the edge of a mesic sand prairie beneath individuals of Lonicera maackii. Three threatened species were found: Lechea intermedia, Orobanche ludoviciana, and Platanthera flava var. helbiola (Herkert and Ebinger 2002, Illinois Endangered Species Protection Board 2005). Dry Sand Prairie: The dry sand prairie at GRSWA was similar to the one located at Foley Nature Preserve (FNP; McFall and Karnes Table 11. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Sparganium eurycarpum vegetation zone in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Summer 2002 Summer 2006 Summer 2007 Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV Sparganium eurycarpum 100 45.55 91.2 -- -- -- 14 0.56 5.4 Persicaria coccinea 100 19.54 53.8 96 33.31 42.9 100 48.73 90.1 Urtica gracilis 84 0.47 22.3 74 18.45 27.2 -- -- -- Schoenoplectus acutus 40 2.25 13.5 -- -- -- -- -- -- Rorippa palustris 44 1.35 13.3 12 0.26 2.2 -- -- -- *Phalaris arundinacea 10 0.05 2.7 2 0.06 0.4 8 1.12 4.0 Amaranthus hybridus 8 0.04 2.1 2 0.01 0.3 -- -- -- *Potentilla norvegica 4 0.02 1.1 6 0.42 1.3 -- -- -- Persicaria pensylvanica -- -- -- 80 24.35 32.9 22 0.70 8.3 *Chenopodium album -- -- -- 94 9.29 22.9 -- -- -- Persicaria punctata -- -- -- 56 9.06 16.6 78 12.70 41.0 *Mentha arvensis -- -- -- 44 6.78 12.7 4 0.02 1.5 Aster praealtus -- -- -- 32 8.05 11.7 2 0.01 0.7 Cuscuta gronovii -- -- -- 38 2.96 8.6 -- -- -- Ambrosia artemisiifolia -- -- -- 24 4.55 7.6 -- -- -- *Cirsium arvense -- -- -- 20 1.80 4.8 -- -- -- Persicaria lapathifolia -- -- -- 12 1.56 3.3 2 0.01 0.7 *Persicaria vulgaris -- -- -- 10 1.26 2.6 4 0.12 1.5 Bolboschoenus fluviatilis -- -- -- 4 0.36 1.0 60 22.95 46.8 Lycopus americanus -- -- -- 2 0.30 0.5 -- -- -- Solidago gigantea -- -- -- 2 0.30 0.5 -- -- -- Totals Bare ground and litter 69.27 25.74 200.0 123.13 6.75 200.0 86.92 23.90 200.0 Table 11. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Sparganium eurycarpum vegetation zone in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 55 1995, McClain et al. 2003). Located in the extreme western part of Lee County (SW1/4 S7 T20N R8E), this preserve covers the entire ridge and slopes of a small dune, and contains a 2.8-ha dry to dry-mesic sand prairie remnant. Schizachyrium scoparium dominated both areas and many forbs were common to both sites. Common forbs at FNP were Euphorbia corolla- ta, Aster ericoides, Echinacea pallida, Coreop- sis palmata, and Ambosia psilostachya, while Amorpha canescens was the common shrub. Species diversity at FNP was higher than at the GRSWA, however, and more conservative prairie species were present as indicated by an FQI of 52.98 and a mean CC of 3.96 (McClain et al. 2003) compared to an FQI of 36.16 and a mean CC of 3.73 at GRSWA. This may be the result of an older, more aggressive management program at the former, athough disturbance prior to public acquisition was probably more Table 12. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species encountered in late summer of 2002 and again in 2006 and 2007 in a Carex lacustris vegetation zone in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Summer 2002 Summer 2006 Summer 2007 Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV Carex lacustris 100 42.80 75.4 100 29.95 32.4 100 38.85 51.7 Persicaria coccinea 100 36.45 69.1 100 55.40 47.8 100 51.20 61.4 Calamagrostis canadensis 38 18.35 30.8 46 8.10 11.5 42 20.40 24.9 Lysimachia thyrsiflora 18 0.82 6.7 4 0.07 0.6 10 0.05 2.1 Lycopus uniflorus 16 0.52 5.7 6 0.08 0.9 4 0.31 1.1 Persicaria punctata 16 0.23 5.4 16 0.13 2.4 16 0.38 3.7 Scutellaria galericulata 4 0.07 1.4 6 0.08 0.9 -- -- -- Teucrium canadense 4 0.07 1.4 32 1.43 5.5 54 4.06 14.6 Rumex orbiculatus 2 0.30 1.0 -- -- -- 2 0.30 0.6 Aster praealtus 2 0.06 0.8 22 4.83 6.0 30 7.94 12.6 Lycopus americanus 2 0.06 0.8 14 1.09 2.7 2 0.06 0.5 Polygonum ramosissimum 2 0.06 0.8 34 1.05 5.5 44 0.57 9.8 *Mentha arvensis 2 0.01 0.7 20 2.25 4.3 8 0.43 2.0 Ambrosia artemisiifolia -- -- -- 100 38.16 37.3 4 0.02 0.9 *Chenopodium album -- -- -- 84 10.83 18.6 -- -- -- Cirsium discolor -- -- -- 26 1.25 4.5 2 0.01 0.4 Galium obtusum -- -- -- 10 3.56 3.6 -- -- -- Solidago gigantea -- -- -- 10 2.21 2.7 4 0.02 0.9 Ambrosia trifida -- -- -- 10 1.71 2.4 -- -- -- Stachys pilosa -- -- -- 12 1.03 2.3 10 0.10 2.2 Oenothera biennis -- -- -- 10 0.44 1.7 -- -- -- *Potentilla norvegica -- -- -- 10 0.15 1.5 4 0.07 1.0 Physalis subglabrata -- -- -- 6 0.42 1.2 -- -- -- Lathyrus palustris -- -- -- 6 0.13 1.0 2 0.06 0.5 Verbena hastata -- -- -- 4 0.31 0.8 -- -- -- Lactuca canadensis -- -- -- 4 0.12 0.7 2 0.01 0.4 Hackelia virginiana -- -- -- 2 0.01 0.3 -- -- -- *Nepeta cataria -- -- -- 2 0.01 0.3 -- -- -- Solidago canadensis -- -- -- 2 0.06 0.3 -- -- -- *Taraxacum officinale -- -- -- 2 0.01 0.3 -- -- -- Carex haydenii -- -- -- -- -- -- 18 2.46 5.7 Iris shrevei -- -- -- -- -- -- 2 0.06 0.5 *Phalaris arundinacea -- -- -- -- -- -- 2 0.06 0.5 Asclepias incarnata -- -- -- -- -- -- 2 0.01 0.4 Euthamia graminifolia -- -- -- -- -- -- 2 0.01 0.4 *Morus alba -- -- -- -- -- -- 2 0.01 0.4 Persicaria vulgaris -- -- -- -- -- -- 2 0.01 0.4 Cardamine parviflora -- -- -- -- -- -- 2 0.01 0.4 Totals 99.80 200.0 164.87 200.0 127.4 7 200.0 Bare ground and litter 1.60 5.14 12.38 Table 12. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer spe- cies encountered in late summer of 2002 and again in 2006 and 2007 in a Carex lacustris vegetation zone in the marsh at the western edge of the Green River State Wildlife Area, Lee County, Illinois. (n=50) (*exotic species) Vol. 39 Art. 256 Illinois Natural History Survey Bulletin Table 13. Density (stems/ha) of seedlings, saplings, and trees, basal area (m2/ha); relative values, importance value (IV), and average diameter (cm) of the woody species (>10.0 cm dbh) encountered in six wooded areas, Green River State Wildlife Area, Lee County, Illinois. (*exotic species) Saplings Species Seed- lings Small Large Trees #/ha Basal Area m2/ha Rel. Den. Rel. Dom. IV Av. Diam. cm Site # 1 Acer saccharinum 1500 700 640 765 38.085 89.5 68.9 158.4 22.8 Populus deltoids -- -- -- 30 10.735 3.5 19.4 22.9 65.0 Salix nigra -- -- -- 35 6.010 4.1 10.9 15.0 45.5 Acer negundo -- -- 40 20 0.385 2.3 0.7 3.0 15.1 Prunus serotina -- -- -- 5 0.065 0.6 0.1 0.7 12.7 Others 7000 3300 60 -- -- -- -- -- -- Totals 8500 4000 740 855 55.280 100.0 100.0 200.0 Site # 2 Acer saccharinum -- -- -- 295 20.365 67.8 73.9 141.7 27.2 Prunus serotina 500 50 40 100 5.590 23.0 20.3 43.3 24.7 Juglans nigra -- -- -- 20 0.820 4.6 3.0 7.6 21.0 Fraxinus pennsylvanica -- 350 -- 20 0.775 4.6 2.8 7.4 20.6 Others 6500 5600 20 -- -- -- -- -- -- Totals 7000 6000 60 435 27.550 100.0 100.0 200.0 Site # 3 Acer saccharinum 2000 -- -- 225 26.345 52.3 77.4 129.7 35.5 Prunus serotina 500 50 80 100 4.290 23.3 12.6 35.9 21.9 Fraxinus pennsylvanica -- 200 40 25 0.530 5.8 1.6 7.4 15.2 Populus deltoides -- -- -- 10 1.325 2.3 3.9 6.2 41.1 Quercus velutina -- -- 40 20 0.515 4.7 1.5 6.2 17.5 Acer negundo -- 100 -- 20 0.375 4.7 1.1 5.8 15.0 *Maclura pomifera -- -- 20 10 0.350 2.3 1.0 3.3 21.1 *Morus alba -- 100 140 10 0.170 2.3 0.5 2.8 14.3 Celtis occidentalis -- 200 20 10 0.120 2.3 0.4 2.7 12.4 Others 13500 6200 -- -- -- -- -- -- -- Totals 16000 6850 340 430 34.020 100.0 100.0 200.0 Site # 4 Acer saccharinum -- 100 20 345 24.690 75.0 80.8 155.8 28.0 Prunus serotina 1000 -- -- 115 5.885 25.0 19.2 44.2 24.5 Others 5000 3300 -- -- -- -- -- -- -- Totals 6000 3400 20 460 30.575 100.0 100.0 200.0 Site # 5 *Morus alba -- 50 260 215 4.330 38.4 13.9 52.3 15.3 Prunus serotina -- 50 -- 100 9.605 17.9 30.7 48.6 30.7 Populus deltoides -- -- -- 35 8.180 6.2 26.1 32.3 53.7 Celtis occidentalis 500 50 160 105 1.805 18.8 5.8 24.6 14.1 Juglans nigra 500 -- -- 55 2.865 9.8 9.2 19.0 29.2 Acer negundo -- 100 20 40 1.675 7.1 5.4 12.5 20.3 Acer saccharinum -- -- -- 5 2.555 0.9 8.2 9.1 80.7 Quercus velutina 1000 -- 20 5 0.215 0.9 0.7 1.6 23.5 Others 4000 5150 -- -- -- -- -- -- -- Totals 6000 5400 460 560 31.230 100.0 100.0 200.0 Site # 6 Prunus serotina 1000 -- -- 225 15.680 60.0 76.0 136.0 29.0 *Robinia pseudoacacia 10000 2200 -- 150 4.960 40.0 24.0 64.0 19.9 Others 4000 1000 -- -- -- -- -- -- -- Totals 15000 3200 -- 375 20.640 100.0 100.0 200.0 Table 13. Density (stems/ha) of seedlings, saplings, and trees, basal area (m2/ha); relative values, importance value (IV), and average diameter (cm) of the woody species (>10.0 cm dbh) encountered in six wooded areas, Green River State Wildlife Area, Lee County, Illinois. (*exotic species) Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 57 important. The low numbers of exotic taxa, along with presence of native and conservative prairie taxa, indicate that both sites were recov- ering from past disturbances. The dry sand prairie at GRSWA is also simi- lar to a small prairie remnant at the Richardson Wildlife Foundation (RWF). Located about 13 km east of Amboy, Lee County, Illinois (S13, S14, S3, S24, T20N R11E), the RWF is located near the southwestern edge of what was the Great Inlet Swamp (Killey 1998, Handel et al. 2003). This swamp covered approximately 12,000 ha, and existed because of the Dewey Dam, a natural limestone obstruction 8 km northeast of the town of Amboy, which pre- vented channel formation by the Green River (Lyman 1901). In the late 1880s, work began to drain this extensive swamp. Efforts to save the swamp and keep it as a wildlife sanctu- ary failed, and by 1901 the swamp was gone (McClain 1992, McClain and Ebinger 2000). After drainage most of the Great Inlet Swamp Table 14. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species (with IV’s >2.0) encountered in 2002, 2003, and 2006 in a successional lowland area cleared of trees in the winter of 2001, Green River State Wildlife Area, Lee County, Illinois. (n=100) (*exotic species) Summer 2006 Summer 2003 Summer 2002 Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV *Phalaris arundinacea 96 28.49 46.0 92 37.49 63.7 76 28.93 52.1 Solidago canadensis 71 15.82 27.6 48 0.89 7.6 -- -- -- Persicaria pensylvanica 71 4.43 13.4 57 4.32 13.5 65 20.52 38.8 *Lactuca serriola 61 4.48 12.4 9 0.17 1.4 -- -- -- *Chenopodium album 79 1.18 10.2 17 0.70 3.3 1 0.15 0.4 Carex cristatella 53 2.28 8.7 -- -- -- -- -- -- Cirsium discolor 45 2.64 8.3 1 0.03 0.1 -- -- -- *Verbascum Thapsus 53 0.61 6.7 7 0.16 1.1 3 0.04 0.6 *Cirsium arvense 28 2.62 6.4 -- -- -- -- -- -- Eupatorium serotinum 40 1.49 6.3 31 1.36 6.0 21 1.20 5.2 Persicaria coccinea 22 2.58 5.7 38 3.48 9.9 26 2.56 7.8 Solidago gigantea 17 2.05 4.5 -- -- -- -- -- -- Ambrosia artemisiifolia 21 1.54 4.2 4 0.59 1.3 -- -- -- Populus deltoides 16 1.95 4.2 40 4.39 11.3 33 2.25 8.6 Oenothera biennis 26 0.62 3.7 -- -- -- 1 0.15 0.4 Acalypha rhomboidea 28 0.39 3.6 14 0.15 2.1 -- -- -- *Fallopia convolvulus 27 0.44 3.5 5 0.08 0.8 -- -- -- Stachys pilosa 13 1.11 2.8 5 0.22 1.0 -- -- -- *Morus tatarica 13 0.56 2.1 18 1.05 3.9 21 0.43 4.2 Solanum carolinense 11 0.64 2.0 -- -- -- -- -- -- Solanum ptychanthum 10 0.05 1.2 9 0.10 1.3 9 0.58 2.4 Bidens vulgata 5 0.08 0.7 7 1.37 2.8 1 0.15 0.4 Phytolacca americana 1 0.38 0.6 3 0.07 0.5 12 0.84 3.1 Carex sp. 2 0.01 0.2 45 1.98 8.7 -- -- -- *Setaria faberi 2 0.01 0.2 15 0.72 3.0 2 0.18 0.6 Conyza canadensis -- -- -- 57 4.47 13.8 -- -- -- *Potentilla norvegica -- -- -- 42 4.97 12.4 26 0.50 5.1 *Persicaria cespitosa -- -- -- 29 1.29 5.7 30 2.58 8.6 Amaranthus tuberculatus -- -- -- 17 0.11 2.5 -- -- -- *Digitaria sanguinalis -- -- -- 12 0.36 2.1 11 0.33 2.3 Cyperus strigosus -- -- -- 8 0.04 1.2 46 0.48 8.4 Eleocharis ovata -- -- -- 7 0.04 1.0 35 0.23 6.2 Lindernia anagallidea -- -- -- -- -- -- 50 2.49 11.9 Rorippa palustris -- -- -- -- -- -- 23 1.19 6.5 Amaranthus albus -- -- -- -- -- -- 14 2.29 5.5 *Amaranthus hybridus -- -- -- -- -- -- 9 1.80 3.9 Rotala ramosior -- -- -- -- -- -- 13 0.55 2.9 Others -- 4.76 16.8 -- 2.49 18.0 -- 2.77 14.1 Totals -- 80.57 200.0 -- 73.09 200.0 -- 73.19 200.0 Average bare ground and litter -- 16.11 -- -- 36.44 -- -- 30.44 -- Table 14. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species (with IV’s >2.0) encountered in 2002, 2003, and 2006 in a successional lowland area cleared of trees in the winter of 2001, Green River State Wildlife Area, Lee County, Illinois. (n=100) (*exotic species) Vol. 39 Art. 258 Illinois Natural History Survey Bulletin was farmed, but many smaller tracts were left for cattle grazing. As of 1999, 15 ha of sand prairie and sedge meadow remnants existed on the RWF. This dry sand prairie remnant at RWF was more mesic than the dry sand prairie at GR- SWA since the dunes in this part of the Green River Lowlands are smaller and the water table is closer to the surface. On this dry sand prairie Sorgastrum nutans dominated, followed by Euthamia graminifolia Schizachyrium scopar- ium, Solidago nemoralis, Liatris aspera, and Viola sagittata. Diversity was low, with only 46 species, including the exotic Rumex aceto- sella, Poa pratensis, and Achillea millefolium, recorded (Handel et al. 2003). The FQI of this dry sand prairie was 29.28 and the mean CC was 4.18. Dry-mesic Sand Prairie: Sorghastrum nutans was the dominant native grass in the dry- mesic sand prairies at both GRSWA and RWF (Handel et al. 2003). Andropogon gerardii, in contrast, was important at GRSWA, but nearly absent at RWF. Dichanthelium villosissimum, a low-growing bunch grass, was fifth in impor- tance at GRSWA but was not encountered at RWF. The dominant forbs on the RWF were Solidago nemoralis, Parthenium integrifolium, and Euthamia graminifolia. Only about half of the species were common to both sites; how- ever, RWF was relatively rich in conservative Table 15. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species (with IVs >2.0) encountered in 2002, 2003, and 2006 in a successional upland area cleared of trees in the winter of 2001, Green River State Wildlife Area, Lee County, Illinois. (n=100) (*exotic species) Summer 2006 Summer 2003 Summer 2002 Species Freq. % Mean Cover IV Freq. % Mean Cover IV Freq. % Mean Cover IV Rubus pensilvanicus 55 14.30 29.4 36 2.67 8.5 25 0.82 6.0 *Verbascum Thapsus 62 5.89 17.4 78 5.57 17.9 27 2.96 11.1 *Chenopodium album 65 3.65 14.5 32 0.41 4.6 44 6.12 21.0 *Lonicera maackii 39 5.93 14.4 88 11.02 27.3 60 4.28 19.6 Prunus serotina 29 5.22 11.9 68 1.91 11.3 22 0.31 4.6 Rubus occidentalis 30 4.78 11.4 16 1.20 3.9 3 0.45 1.4 Ambrosia artemisiifolia 43 3.47 11.1 26 1.44 5.3 4 0.60 2.1 *Robinia pseudoacacia 36 3.11 9.7 30 2.20 7.0 23 0.87 5.8 Conyza canadensis 45 2.10 9.3 96 26.50 51.3 5 0.37 1.6 Lactuca canadensis 44 1.04 7.6 -- -- -- 3 0.07 0.5 Solidago canadensis 26 2.64 7.6 4 0.07 0.6 2 0.06 0.4 Cyperus lupulinus 44 0.98 7.5 68 3.09 13.0 3 0.04 0.5 *Alliaria petiolata 41 0.87 6.9 -- -- -- 41 2.18 11.8 Phytolacca americana 14 2.52 5.8 24 1.29 4.9 83 11.16 38.8 Prunus virginiana 15 2.46 5.8 8 0.33 1.5 17 0.53 4.0 Smilacina stellata 20 0.50 3.4 2 0.06 0.4 2 0.02 0.4 Dichanthelium villosissimum 14 0.54 2.7 4 0.12 0.7 4 0.10 0.9 *Phalaris arundinacea 10 0.64 2.4 8 0.67 2.0 2 0.18 0.7 Solanum carolinense 9 0.73 2.3 8 0.19 1.3 -- -- -- Oxalis stricta 14 0.07 2.0 10 0.05 1.3 1 0.01 0.2 Parthenocissus quinquefolia 8 0.43 1.8 8 0.67 2.0 6 0.30 1.7 Carex molesta 5 0.39 1.3 14 1.09 3.3 -- -- -- Quercus velutina 3 0.45 1.1 14 0.22 2.0 1 0.03 0.3 Dichanthelium oligosanthes 5 0.08 0.8 28 2.29 6.9 7 0.28 1.7 Muhlenbergia schreberi 3 0.02 0.4 12 1.00 3.0 7 0.51 2.2 Solanum ptychanthum 2 0.01 0.3 14 0.17 2.0 67 8.88 31.0 Chenopodium standleyanum 1 0.03 0.2 -- -- -- 11 1.23 4.5 Polygala polygama -- -- -- 20 0.54 3.3 10 0.05 1.8 Dichanthelium acuminatum -- -- -- 14 0.80 2.9 6 0.06 1.1 Cyperus schweinitzii -- -- -- 8 0.38 1.6 64 1.36 13.7 Others -- 2.34 11.0 -- 1.35 10.2 -- 1.11 10.6 Totals -- 65.19 200.0 -- 67.30 200.0 -- 44.94 200.0 Average bare ground and litter -- 26.68 -- -- 31.68 -- -- 51.40 -- Table 15. Frequency (%), mean cover (% of total cover), and importance value (IV) of the ground layer species (with IVs >2.0) encountered in 2002, 2003, and 2006 in a successional upland area cleared of trees in the winter of 2001, Green River State Wildlife Area, Lee County, Illinois. (n=100) (*exotic species) Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 59 species that were not found at GRSWA. The FQI was 41.88 and the mean CC was 4.44 at RWF (compared to FQI of 37.77, mean CC of 3.74 at GRSWA). Mesic Sand Prairie: The mesic to wet-mesic sand prairies at RWF and GRSWA differed in species composition (Handel et al. 2003). On both sites Sorghastrum nutans and Andropogon gerardii were the dominant tall grasses. Also, at both sites forb diversity was high, but few of the species encountered at the GRSWA were found at RWF, and except for the dominant tall grasses there was almost no similarity between the two sites. The mesic sand prairie at RWF had a higher FQI and mean CC than at GR- SWA. Overall, there were fewer native prairie species at GRSWA and most were not conser- vative species. Past destructive management practices (including food plot plantings, lack of fire, and equestrian use) at GRSWA prior to 1993 were probably responsible for these dif- ferences. Wet Sand Prairie: The only wet sand prairie examined in the Green River Lowlands was associated with a sedge meadow/mesic prairie area at GRSWA. This plant community is simi- lar in species composition to wet “black soil” prairies with Spartina pectinatus, Calamagros- tis canadensis, Thelypteris palustris and vari- ous Carex species common (White and Madany 1978). The wet sand prairie at GRSWA, with 102 taxa, had the highest species diversity of all communities encountered. Many were rare species with very specific habitat requirements, some of which were common throughout the wet prairie. Sedge Meadow: Sedge meadows are rela- tively common in the preserves of the Green River Lowlands. Two were studied at GRSWA, whereas three at RWF had earlier been exam- ined (Handel et al. 2003). All were similar in having extensive hummocks of Carex haydenii, the dominant species. The species commonly encountered at RWF included Onoclea sen- sibilis, Thelypteris palustris, Calamagros- tis canadensis, Helianthus grosseserratus, Boehmeria cylindrica, Solidago gigantea, and Galium obtusum; many of the same species encountered at the GRSWA sedge meadows. The sedge meadows at RWF averaged be- tween 39 and 54 species, compared to 25 to 29 species at GRSWA. The reason for the lower species diversity at the GRSWA is not known, but is undoubtedly related to the nature of past disturbances, and more active management, especially water table manipulation, at RWF. Marsh: The only marsh examined in the Green River Lowlands, located at the western edge of the GRSWA, was surveyed in 2002, subjected to an uncontrolled burn in 2005, and surveyed again in late summer of 2006 and 2007. During 2002 species diversity was very low, composed mainly of species found in many marsh communities throughout most of Illinois (White and Madany 1978). The first year after the 2005 fire, many native weedy species became important, whereas the original dominant species were either absent or present in low numbers. By 2007 many of these native weedy species were greatly reduced in numbers or were absent altogether, whereas many of the species dominant in 2002 were recovering. One exception was Sparganium eurycarpum, which had not recovered by 2007. It appears that this species does not do well after hot fires, many of the rhizomes likely did not survive. Many of the less abundant species that were present in 2002 were not observed in the later surveys as they were never important stand components. Sand Forest: Based on General Land Of- fice (GLO) survey notes and plats, the pre- settlement sand deposits of the Green River Lowlands were dominated by sand prairies and marshes. The dominant tree on sand dunes was Quercus velutina, mostly occurring as scattered individuals on dune ridges and protected sites. These savannas consisted of open-growth trees and ground cover dominated by sand prairie grasses and forbs (Curtis 1959, Bray 1960, Nuzzo 1986, White and Madany 1978). In dry sand savannas the soil lacked a dark A horizon and the ground cover was composed of many prairie species with the dominant bunchgrasses, which were typically less than 1 m tall. These dry sand savannas and forests were associ- ated with dune and swale topography, which probably limited the severity of fires. Common lowland species of the Green River Lowlands were probably Acer saccharinum, Celtis oc- cidentalis, Fraxinus pennsylvanica, Populus deltoides, Prunus serotina, and Salix nigra. Frequent prairie fires prevented these fast growing tree species from covering large areas Vol. 39 Art. 260 Illinois Natural History Survey Bulletin of the wetland and lower dune slopes (Mc- Clain and Elzinga 1994). These fast-growing, fire-sensitive, shade-intolerant taxa were all common forest components at GRSWA during this study. The forests present at GRSWA during this study were of recent origin. Post-settlement fire supression had increased the acreage of sand forest at the expense of sand savan- nas (White and Madany 1978, Anderson and Brown 1986, Anderson 1991, Abrams 1992). These forests, with 80 to 100% canopy cover, had eliminated the common prairie and marsh plants associated with the dune and swale to- pography typical of Illinois sand deposits. Management: The management of prairie and marsh communities at GRSWA since 1993, which has included the use of fire on a regular basis and the active removal of brush and trees, has been important in improving the quality of these communities. The high importance values of some exotic species, particularly Phalaris arundinacea, indicated that some areas were not recovering rapidly from past disturbances. The presence of the native and conservative prairie taxa, however, indicated that the management practices had, in part, been successful. The use of fire is imperative if the upland sand prairie communities are go- ing to increase in quality and species diversity (Bowles et al. 2003). ACKNOWLEDGMENTS The authors thank the Illinois Department of Natural Resources for funding parts of this project through the Illinois Wildlife Preserva- tion Fund as well as other funding sources, the Illinois Nature Preserves Commission for allowing access to the nature preserves, Dr. Gordon Tucker, Eastern Illinois University, for his help in identification of the Cyperaceae, and Ms. Katherine J. Hunter, Illinois Natural His- tory Survey, for digitizing the data on woody encroachment. P. Sorensen and an anonymous reviewer provided constructive comments on the manuscript. Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 61 LITERATURE CITED Abrams, M.D. 1992. Fire and the development of oak forests. BioScience 42:346– 353. Anderson, R.C. 1991. Presettlement forest of Illinois. Pages 9–19 in G.V. Burger, J.E. Ebinger, and G.S. Wilhelm, eds. Proceedings of the Oak Woods Man- agement Workshop. Eastern Illinois University, Charleston. 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Illinois Natural Areas Inven- tory, Urbana. Willman, H.B., and J.C. Frye. 1970. Pleisto- cene stratigraphy of Illinois. Illinois State Geological Survey Bulletin 94:1–204. Zwicker, S.E. 1985. Soil survey of Lee County, Illinois. United States Department of Agriculture, Soil Conservation Service in cooperation with the Illinois Agri- cultural Experiment Station, Cham- paign. ix+236 pp. Vol. 39 Art. 264 Illinois Natural History Survey Bulletin APPENDIx I Vascular plant species encountered at Green River State Wildlife Area, Lee County, Illinois, are listed alphabetically by family under major plant groups. Collecting numbers preceded by an E (John E. Ebinger) are deposited in the Stover-Ebinger Herbarium, Eastern Illinois University, Charleston, Illinois (EIU). Collecting numbers preceded by a P (Loy R. Phillippe) are deposited in the Illinois Natural History Survey Herbarium, Champaign. (ILLS). (*exotic species) FERNS AND FERN-ALLIES Aspleniaceae Asplenium platyneuron (L.) Oakes: P32588 Dryopteridaceae Athyrium filix-femina (L.) Martens ssp. angustum (Willd.) R.T. Clausen: P32587 Dryopteris carthusiana (Villars) H.P. Fuchs: P32576 Dryopteris cristata (L.) Gray: P31662 Equisetaceae Equisetum arvense L.: P31501 Equisetum x ferrissii Clute: P31638 Equisetum hyemale L.: P32602 Equisetum laevigatum A. Br.: P31644 Onocleaceae Onoclea sensibilis L.: P32370 Ophioglossaceae Botrychium dissectum Spreng.: P32530 Botrychium matricariifolium (Doll.) A. Br.: P31628 Botrychium virginianum (L.) Sw.: P31608 Osmundaceae Osmunda claytoniana L.: P31483 Osmunda regalis L.: P31577 Thelypteridaceae Thelypteris palustris Schott: P32451 GYMNOSPERMS Cupressaceae Juniperus virginiana L.: P31530 Pinaceae *Larix decidua Mill.: P31551 *Pinus banksiana Lamb.: P31529 *Pinus echinata Mill.: P32494 *Pinus strobus L.: P32606 *Pinus sylvestris L.: P32619 *Pseudotsuga taxifolia Britt.: P32675 Taxodiaceae *Taxodium distichum (L.) Rich.: P32622 Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 65 MONOCOTS Alismataceae Alisma subcordatum Raf.: P32411 Alisma triviale Pursh: P32625 Sagittaria latifolia Willd.: P32365 Amaryllidaceae Hypoxis hirsuta (L.) Coville: P31507 Commelinaceae *Commelina communis L.: P32678 Tradescantia ohiensis Raf.: P31474 Cyperaceae Bolboschoenus fluviatilis (Torr.) Sojak: P31593 Bulbostylis capillaris (L.) C.B. Clarke: P36135 Carex bicknellii Britt.: P31682 Carex brevior (Dewey) Mack.: P31564 Carex buxbaumii Wahl.: P31613 Carex conoidea Schk.: P31504 Carex cristatella Britt.: P31653 Carex davisii Schwein. & Torr.: P31579 Carex festucacea Schk.: P31589 Carex haydenii Dewey: P31587 Carex lacustris Willd.: P34952 Carex molesta Mack.: P35666 Carex muhlenbergii Schk.: P31562 Carex normalis Mack.: P31713 Carex pellita Willd.: P31633 Carex pensylvanica Lam.: P32641 Carex scoparia Schk.: P36143 Carex stipata Muhl.: P31592 Carex suberecta (Olney) Britt.: P31697 Carex swanii (Fern.) Mack.: P31611 Carex tonsa (Fern.) Bickn.: P31513 Carex tribuloides Vahl: P34684 Carex vesicaria L.: P31508 Carex vulpinoidea Michx.: P31687 Cyperus esculentus L.: P32489 Cyperus lupulinus (Spreng.) Marcks var. macilentus (Fern.) Marcks: P32486 Cyperus schweinitzii Torr.: P32608 Cyperus squarrosus L.: P34699 Cyperus strigosus L.: P32412 Eleocharis acicularis (L.) Roem. & Schultes: P32417 Eleocharis compressa Sull.: P31614 Eleocharis ovata (Roth) Roem. & Schultes var. detonsa (Gray) Mohlenbr.: P32596 Eleocharis ovata (Roth) Roem. & Schultes var. obtusa (Willd.) Kukenth: P32415 Eleocharis verrucosa (Svenson) Harms: P31673 Eleocharis wolfii Gray: P31615 Fimbristylis autumnalis (L.) Roem. & Schultes: P32687 Schoenoplectus acutus (Muhl.) A. Love & D. Love: P32501 Schoenoplectus heterochaetus (Chase) Sojak: P31683 Scirpus atrovirens Willd.: P32623 Vol. 39 Art. 266 Illinois Natural History Survey Bulletin Scirpus cyperinus (L.) Kunth: P32373 Scirpus pendulus Muhl.: P31704 Scleria triglomerata Michx.: P31671 Iridaceae *Iris flavescens DC.: P35672 Iris shrevei Small: P31581 Sisyrinchium campestre Bickn.: P31511 Juncaceae Juncus acuminatus Michx.: P32413 Juncus dudleyi Wieg.: E28953 Juncus effusus L.: P32473 Juncus greenei Oakes & Tuckerm.: P31678 Juncus interior Wieg.: P31695 Juncus marginatus Rostk.: P32477 Juncus tenuis Willd.: P31696 Juncus torreyi Coville: P32476 Lemnaceae Lemna minor L.: P32626 Lemna trisulca L.: P31657 Liliaceae Allium canadense L.: P31685 *Asparagus officinalis L.: P31618 *Hemerocallis fulva (L.) L.: P34599 Lilium michiganense Farw.: P35863 Maianthemum canadense Desf. var. canadense: P31607 Polygonatum commutatum (Schult.) A. Dietr.: P31605 Smilacina stellata (L.) Desf.: P31500 Orchidaceae Corallorhiza odontorhiza (Willd.) Nutt.: P32631 Goodyera pubescens (Willd.) R. Br.: P32367 Liparis liliifolia (L.) Rich.: P32418 Liparis loeselii (L.) Rich.: P32577 Platanthera flava (L.) Lindl. var. herbiola (R. Br.) Luer: P31654 Spiranthes cernua (L.) Rich.: P32431 Spiranthes ovalis Lindl.: P34968 Poaceae Agrostis gigantea Roth: P31560 Agrostis hyemalis (Walt.) BSP.: R.Evers 108119 Alopecurus carolinianus Walt.: P35654 Andropogon gerardii Vitman: P32354 Aristida basiramea Engelm.: P32521 Aristida intermedia Scribn. & Ball: P32497 Aristida oligantha Michx.: P32573 Aristida tuberculosa Nutt.: P32560 *Avena sativa L.: P32663 Bouteloua curtipendula (Michx.) Torr.: E28888 Bouteloua hirsuta Lag.: P32569 *Bromus commutatus Schrad.: P31718 Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 67 *Bromus inermis Leyss.: P31572 *Bromus tectorum L.: P31540 Calamagrostis canadensis (Michx.) P. Beauv.: P31659 Cenchrus longispinus (Hack.) Fern.: E28917 Cinna arundinacea L.: P32531 *Dactylis glomerata L.: P31604 Dichanthelium acuminatum (Sw.) Gould & Clark var. fasciculatum (Torr.) Freckm.: P31702 Dichanthelium depauperatum (Muhl.) Gould: observed Dichanthelium oligosanthes (Schult.) Gould var. scribnerianum (Nash) Gould: P31475 Dichanthelium perlongum (Nash) Freckm.: P31557 Dichanthelium villosissimum (Nash) Freckm.: P31569 *Digitaria ischaemum (Schreb.) Schreb.: P32381 *Digitaria sanguinalis (L.) Scop.: E28891 *Echinochloa crus-galli (L.) P. Beauv.: P32414 Echinochloa muricata (Michx.) Fern. var. muricata: P32515 Echinochloa walteri (Pursh) Heller: P34977 *Eleusine indica (L.) Gaertn.: P32648 Elymus canadensis L.: P32572 Elymus villosus Muhl.: P32667 Elymus virginicus L.: P32463 *Elytrigia repens (L.) Desv.: E28909 *Eragrostis cilianensis (All.) Vign.: P34696 Eragrostis frankii C.A. Meyer var. frankii: P32532 Eragrostis hypnoides (Lam.) BSP.: P36136 Eragrostis pectinacea (Michx.) Nees: P34697 Eragrostis spectabilis (Pursh) Steud.: P32427 *Festuca arundinacea Schreb.: P35661 *Festuca pratensis Huds.: E28907 Festuca subverticillata (Pers.) E.B. Alexeev.: P35657 Glyceria septentrionalis Hitchc.: P31652 Glyceria striata (Lam.) Hitchc.: P31656 Heterostipa spartea (Trin.) Barkworth: P31599 Hordeum jubatum L.: P32484 Hordeum pusillum Nutt.: P31583 Koeleria macrantha (Ledeb.) Spreng.: P31602 Leersia oryzoides (L.) Swartz: P32448 Leersia virginica Willd.: P32581 Leptoloma cognatum (Schult.) Chase: E28956 *Lolium perenne L.: P34695 *Miscanthus sacchariflorus (Maxim.) Hack.: P37113 Muhlenbergia frondosa (Poir.) Fern.: P32524 Muhlenbergia mexicana (L.) Trin.: P32375 Muhlenbergia schreberi J.F. Gmel.: P32384 Panicum capillare L.: P32534 Panicum dichotomiflorum Michx.: P32533 Panicum virgatum L.: E28947 Paspalum bushii Nash: E28957 *Phalaris arundinacea L.: P31568 *Phleum pratense L.: E28906 *Phragmites australis (Cav.) Trin.: P32506 *Poa annua L.: P35644 *Poa compressa L.: P31597 *Poa pratensis L.: P31494 Schizachyrium scoparium (Michx.) Nash: P34677 Vol. 39 Art. 268 Illinois Natural History Survey Bulletin *Secale cereale L.: P35651 *Setaria faberi R.A.W. Herrm.: P32363 Setaria glauca (L.) P. Beauv.: P32438 *Setaria viridis (L.) P. Beauv.: E28916 Sorghastum nutans (L.) Nash: P32350 Spartina pectinata Link: P32374 Sporobolus cryptandrus (Torr.) Gray: P32426 Sporobolus heterolepis (Gray) Gray: P32496 Sporobolus vaginiflorus (Torr.) A. Wood: P32491 Tridens flavus (L.) Hitchc.: P32586 Triplasis purpurea (Walt.) Chapm.: P32604 *Triticum aestivum L.: P35659 Vulpia octoflora (Walt.) Rydb. var. glauca (Nutt.) Fern.: P31567 Vulpia octoflora (Walt.) Rydb. var. tenella (Willd.) Fern.: P35658 Smilacaceae Smilax lasioneuron Hook.: P32518 Smilax tamnoides L.: P32582 Sparganiaceae Sparganium eurycarpum Engelm.: P32504 Typhaceae Typha angustifolia L.: P34971 Typha latifolia L.: P32595 DICOTS Aceraceae Acer negundo L.: P31545 Acer saccharinum L.: P31368 Amaranthaceae Amaranthus albus L.: P32593 *Amaranthus hybridus L.: P32652 *Amaranthus powellii S. Wats.: P32566 *Amaranthus retroflexus L.: P32660 Amaranthus tuberculatus (Moq.) J. Sauer: P32565 Froelichia floridana (Nutt.) Moq.: E28940 Froelichia gracilis (Hook.) Moq.: P32487 Anacardiaceae Rhus aromatica Ait. var. arenaria (Greene) Fern.: P31518 Rhus glabra L.: P31710 Toxicodendron radicans (L.) Kuntze: P31723 Apiaceae Angelica atropurpurea L.: P34607 Cicuta maculata L.: P31655 *Conium maculatum L.: P35650 Cryptotaenia canadensis (L.) DC.: P31660 *Daucus carota L.: E28901 Eryngium yuccifolium Michx.: P32544 Osmorhiza claytonii (Michx.) C.B. Clarke: P31612 Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 69 Osmorhiza longistylis (Torr.) DC.: P31482 Oxypolis rigidior (L.) Raf.: P32467 *Pastinaca sativa L.: P31570 Polytaenia nuttallii DC.: P31601 Sanicula canadensis L. var. canadensis: P31665 Sanicula odorata (Raf.) Pryer & Phillippe: P32645 Sium suave Walt.: P32509 Zizia aurea (L.) Koch: P31512 Apocynaceae Apocynum cannabinum L.: E28918 Apocynum sibiricum Jacq.: P31686 Ascelpiadaceae Asclepias amplexicaulis Small: P31582 Asclepias hirtella (Pennell) Woodson: P31670 Asclepias incarnata L.: E28919 Asclepias sullivantii Engelm.: P31690 Asclepias syriaca L.: P31667 Asclepias verticillata L.: E28944 Asclepias viridiflora Raf.: P31647 Asteraceae *Achillea millefolium L.: P31563 Ageratina altissima (L.) R.M. King & H. Robins.: E28897 Ambrosia artemisiifolia L.: P32353 Ambrosia psilostachya DC.: E28959 Ambrosia trifida L.: P32485 Antennaria neglecta Greene: P31491 Antennaria plantaginifolia (L.) Hook.: P32643 *Arctium minus Schk.: P36134 Arnoglossum plantagineum Raf.: P34676 Artemisia campestris L.: P32391 Aster ericoides L.: P32551 Aster lanceolatus Willd.: P32540 Aster novae-angliae L.: P32466 Aster oblongifolius Nutt.: P32689 Aster ontarionis Wieg.: P32590 Aster oolentangiensis Riddell: P32638 Aster pilosus Willd.: P32555 Aster praealtus Poir.: P34953 Aster puniceus L.: P32460 Aster sericeus Vent.: P32664 Bidens bipinnata L.: P32629 Bidens cernua L.: P32644 Bidens comosa (Gray) Wieg.: P32539 Bidens coronata (L.) Britt.: P32455 Bidens vulgata Greene: P32526 Boltonia asteroides (L.) L’Hér var. recognita (Fern. & Grisc.) Cronq.: P32420 Brickellia eupatorioides (L.) Shinners: E28949 Chrysopsis camporum Greene: P31565 *Cichorium intybus L.: P34692 *Cirsium arvense (L.) Scop.: E28914 Cirsium discolor (Muhl.) Spreng.: P32390 Vol. 39 Art. 270 Illinois Natural History Survey Bulletin *Cirsium vulgare (Savi) Tenore: P32592 Conoclinium coelestinum (L.) DC.: observed Conyza canadensis (L.) Cronq.: P32352 Coreopsis lanceolata L.: P31558 Coreopsis palmata Nutt.: P32495 Echinacea pallida (Nutt.) Nutt.: P31706 Erechtites hieracifolia (L.) Raf.: P32358 Erigeron annuus (L.) Pers.: P31715 Erigeron philadelphicus L.: P31584 Erigeron strigosus Muhl.: P31561 Eupatoriadelphus maculatus (L.) R.M. King & H. Robins.: P32456 Eupatoriadelphus purpureus (L.) R.M. King & H. Robins.: P32671 Eupatorium altissimum L.: P32440 Eupatorium perfoliatum L.: P32369 Eupatorium serotinum Michx.: P32446 Euthamia graminifolia (L.) Nutt.: P34949 Euthamia gymnospermoides Greene: P32349 Helenium autumnale L.: P32464 *Helianthus annuus L.: P34685 Helianthus grosseserratus Martens: E28926 Helianthus occidentalis Riddell: E28943 Helianthus pauciflorus Nutt.: P32428 Helianthus tuberosus L.: P32408 Heliopsis helianthoides (L.) Sweet: P32442 Hieracium longipilum Torr.: E28942 Ionactis linariifolius (L.) Greene: P32570 Krigia virginica (L.) Willd.: P31471 Lactuca canadensis L.: P32366 Lactuca floridana (L.) Gaertn.: P34689 *Lactuca serriola L.: P32653 *Leucanthemum vulgare Lam.: P31711 Liatris aspera Michx.: P32421 Liatris pycnostachya Michx.: E28931 *Matricaria discoidea DC.: P31539 Oligoneuron rigidum (L.) Small: P32424 Parthenium integrifolium L.: P31703 Prenanthes racemosa Michx.: P32610 Pseudognaphalium obtusifolium (L.) Hilliard & Burtt.: P32382 Ratibida pinnata (Vent.) Barnh.: P32441 Rudbeckia hirta L.: P31643 Rudbeckia subtomentosa Pursh: P32377 Senecio plattensis Nutt.: P31492 Silphium integrifolium Michx.: E28928 Silphium laciniatum L.: P32616 Silphium terebinthinaceum Jacq.: P32682 Solidago canadensis L.: P32549 Solidago gigantea Ait.: P32360 Solidago missouriensis Nutt. var. fasciculata Holz.: E28950 Solidago nemoralis Ait.: P32557 Solidago speciosa Nutt.: P32522 *Sonchus arvensis L. var. glabrescens Grab. & Wimm.: P32585 *Sonchus asper (L.) Hill: P34608 *Taraxacum officinale Weber: P31479 *Tragopogon dubius Scop.: P31485 Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 71 *Tragopogon pratensis L.: P35664 Vernonia fasciculata Michx.: P32434 Xanthium strumarium L. var. canadense (Mill.) Torr. & Gray: P32568 Balsamiaceae Impatiens pallida Nutt.: observed Bignoniaceae Campsis radicans (L.) Seem.: E28900 *Catalpa speciosa Warder: P31708 Boraginaceae Hackelia virginiana (L.) I.M. Johnston: P32385 Lithospermum croceum Fern.: P31473 Lithospermum incisum Lehm.: P32630 Brassicaceae *Alliaria petiolata (Bieb.) Cavara & Grande: P31480 *Arabidopsis thaliana (L.) Heynh.: P35643 Arabis glabra (L.) Bernh.: P31719 *Barbarea vulgaris R. Br.: P31484 *Berteroa incana (L.) DC.: P31535 *Capsella bursa-pastoris (L.) Medic.: P31369 Cardamine bulbosa (Muhl.) BSP.: P31588 Cardamine pensylvanica Willd.: P31610 Draba reptans (Lam.) Fern.: P31516 *Erysimum cheiranthoides L.: P31527 *Erysimum inconspicuum (S. Wats.) MacM.: P31642 *Erysimum repandum L.: P35648 *Hesperis matrionalis L.: P34610 *Lepidium campestre (L.) R. Br.: P31525 *Lepidium densiflorum Schrad.: P31677 Lepidium virginicum L.: P31476 Nasturtium officinale R. Br.: P31609 Rorippa palustris (L.) Besser var. fernaldiana (Butters & Abbe) Stuckey: P32600 Rorippa sessiliflora (Nutt.) A. Hitchc.: P32564 *Sisymbrium altissimum L.: P31536 *Sisymbrium loeselii L.: E28905 *Thlaspi arvense L.: P31499 Caesalpiniaceae Chamaecrista fasciculata (Michx.) Greene: E28936 Campanulaceae Campanula aparinoides Pursh: P32457 Campanulastrum americanum (L.) Small: E28896 Lobelia cardinalis L.: P36133 Lobelia siphilitica L.: P32425 Lobelia spicata Lam.: P31575 Triodanis perfoliata (L.) Neiuwl.: P31622 Cannabinaceae *Cannabis sativa L.: P31646 Vol. 39 Art. 272 Illinois Natural History Survey Bulletin Capparaceae Polanisia dodecandra (L.) DC.: P32655 Caprifoliaceae *Lonicera x bella Zabel: P 31519, P 32520 *Lonicera maackii (Rupr.) Maxim.: P 31481 *Lonicera morrowii Gray: P 35649 Sambucus canadensis L.: P 31707 *Viburnum opulus L.: P 31552 Viburnum prunifolium L.: P 35667 Caryophyllaceae *Arenaria serpyllifolia L.: P35647 *Cerastium fontanum Baum: P31497 Cerastium nutans Raf.: P31526 *Dianthus armeria L.: P31645 *Holosteum umbellatum L.: P31541 *Saponaria officinalis L.: E28915 Silene antirrhina L.: P31641 *Silene pratensis (Spreng.) Godron & Gren.: P31495 *Stellaria media (L.) Cyrillo: P31496 Celastraceae Celastrus scandens L.: P32674 Chenopodiaceae *Chenopodium album L.: P32510 Chenopodium standleyanum Aellen: P32393 *Monolepis nuttalliana (Roem. & Schultes) Greene: P35646 Cistaceae Helianthemum bicknellii Fern.: P31595 Helianthemum canadense (L.) Michx.: P32668 Lechea intermedia Britt.: P37119 Lechea stricta Leggett: P32603 Lechea tenuifolia Michx.: E28958 Convolvulaceae Calystegia sepium (L.) R. Br.: P31674 Cornaceae Cornus obliqua Raf.: P31712 Cornus racemosa Lam.: P31714 Cornus sericea L.: P31544 Corylaceae Corylus americana Walt.: P32519 Crassulaceae *Sedum telephium L.: P36137 Cucurbitaceae Echinocystis lobata (Michx.) Torr. & Gray: P32436 Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 73 Cuscutaceae Cuscuta gronovii Willd. var. gronovii: E28960 Cuscuta pentagona Engelm.: P32627 Elaeagnaceae *Elaeagnus umbellata Thunb.: P31550 Euphorbiaceae Acalypha gracilens Gray var. gracilens: P32529 Acalypha rhomboidea Raf.: E28899 Chamaesyce maculata (L.) Small: P32517 Chamaesyce nutans (Lag.) Small: P32439 Euphorbia corollata L.: E28945 Poinsettia dentata (Michx.) Kl. & Garcke: P32656 Fabaceae Amorpha canescens Pursh: E28941 Amorpha fruticosa L.: P31619 Amphicarpaea bracteata (L.) Fern. var. bracteata: observed Apios americana Medic.: P32673 Astragalus canadensis L.: P34602 Baptisia alba (L.) Vent: E28952 Baptisia bracteata Ell. var. glabrescens (Larisey) Isely: P31490 Dalea purpurea Vent.: E28948 Desmodium canadense (L.) DC.: E28935 Desmodium illinoense Gray: P32443 *Kummerowia striata (Thunb.) Schind.: P32387 Lathyrus palustris L. var. palustris: P31692 Lespedeza capitata Michx.: P32422 *Lespedeza cuneata (Dum.-Cours.) G. Don: P32688 *Lotus corniculatus L.: P34674 *Medicago lupulina L.: P31498 *Medicago sativa L.: P31640 *Melilotus albus Medic.: P31648 *Melilotus officinalis (L.) Pallas: P31639 *Robinia pseudoacacia L.: P32575 Tephrosia virginiana (L.) Pers.: P31668 *Trifolium campestre Schreb.: P31722 *Trifolium hybridum L.: P31721 *Trifolium pratense L.: P31573 *Trifolium repens L.: P31488 *Vicia villosa Roth: P31636 Fagaceae Quercus velutina Lam.: P31478 Gentianaceae Gentiana andrewsii Griseb.: P32545 Gentiana puberulenta J. Pringle: P32640 Grossulariaceae Ribes americanum Mill.: P31549 Ribes missouriense Nutt.: P34609 Vol. 39 Art. 274 Illinois Natural History Survey Bulletin Hypericaceae Hypericum canadense L.: P32599 Hypericum gentianoides (L.) BSP.: P32665 *Hypericum perforatum L.: E28908 Hypericum punctatum Lam.: E28932 Hypericum sphaerocarpum Michx.: P32611 Triadenum fraseri (Spach) Gl.: P32447 Juglandaceae Juglans nigra L.: P32618 Lamiaceae *Chaiturus marrubiastrum (L.) Reichenb.: P32601 *Glechoma hederacea L.: P32658 Hedeoma hispida Pursh: P31627 *Lamium amplexicaule L.: P35645 *Leonurus cardiaca L.: E28911 Lycopus americanus Muhl.: P32361 Lycopus uniflorus Michx.: P32458 *Mentha arvensis L.: E28913 Monarda fistulosa L.: E28938 Monarda punctata L.: E28946 *Nepeta cataria L.: E28895 Physostegia speciosa (Sweet) Sweet: P34976 Physostegia virginiana (L.) Benth.: P32462 *Prunella vulgaris L.: E28912 Pycnanthemum virginianum (L.) Dur. & B.D. Jacks.: E28925 *Salvia reflexa Hornem.: P32661 Scutellaria galericulata L.: P32500 Scutellaria lateriflora L.: P32355 Scutellaria leonardii Epling: P35665 Stachys pilosa Nutt. var. homotricha (Fern) Mohlenbr.: P31701 Teucrium canadense L.: E28923 Linaceae Linum sulcatum Riddell: P32397 Lythraceae Ammannia coccinea Rottb.: P32567 Lythrum alatum Pursh: P31672 *Lythrum salicaria L.: P32371 Rotala ramosior (L.) Koehne: P32597 Malvaceae *Abutilon theophrastii Medic.: P32584 Hibiscus laevis All.: P32503 *Malva neglecta Wallr.: P31538 *Sida spinosa L.: P32583 Melastomataceae Rhexia virginica L.: E28934 Molluginaceae *Mollugo verticillata L.: E28890 Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 75 Moraceae *Maclura pomifera (Raf.) Schneider: P32499 *Morus alba L.: P34606 *Morus tatarica L.: P34605 Nyctaginaceae *Mirabilis nyctaginea (Michx.) MacM.: P31571 Oleaceae Fraxinus pennsylvanica Marsh.: P31546 Onagraceae Epilobium coloratum Spreng.: P32511 Epilobium leptophyllum Raf.: P32453 Gaura biennis L.: P32635 Ludwigia alternifolia L.: E28933 Ludwigia palustris (L.) Ell.: P32637 Ludwigia polycarpa Short & Peter: P32356 Oenothera biennis L.: P32348 Oenothera clelandii W. Dietr., Raven, & W.L. Wagner: E28951 Orobanchaceae Orobanche ludoviciana Nutt.: P32607 Oxalidaceae Oxalis stricta L.: P31486 Oxalis violacea L.: P31505 Phrymaceae Phryma leptostachya L.: P32386 Phytolaccaceae Phytolacca americana L.: E28894 Plantaginaceae Plantago aristata Michx.: P31684 *Plantago lanceolata L.: P31576 Plantago patagonica Jacq.: P32445 Plantago rugelii Decne.: P32351 Polemoniaceae Phlox bifida Beck: P31524 Phlox maculata L.: P31699 Polygalaceae Polygala polygama Walt.: P31559 Polygala sanguinea L.: E28930 Polygala verticillata L. var. isocycla Fern.: P32392 Polygonaceae Antenoron virginianum (L.) Roberty & Vautier: P32670 *Fallopia convolvulus (L.) A. Love: P34601 Fallopia scandens (L.) Holub: P32430 Persicaria amphibium (L.) S.F. Gray: E28922 Vol. 39 Art. 276 Illinois Natural History Survey Bulletin *Persicaria cespitosa (Blume) Nakai: P34604 Persicaria coccinea (Muhl.) Greene: P40241 *Persicaria hydropiper (L.) Opiz: P32624 Persicaria hydropiperoides (Michx.) Small: P31680 Persicaria lapathifolia (L.) S.F. Gray: P32512 Persicaria pensylvanica (L.) Small: P32362 Persicaria punctata (Ell.) Small: P32364 *Persicaria vulgaris Webb & Moq.: P32651 Polygonum achoreum S.F. Blake: P34688 *Polygonum arenastrum Boreau: P32657 Polygonum ramosissimum Michx.: P32516 Polygonum tenue Michx.: P32398 *Rumex acetosella L.: P31533 Rumex altissimus Wood: P31689 *Rumex crispus L.: P31694 Rumex orbiculatus Gray: P32508 Tracaulon sagittatum (L.) Small: P32376 Portulacaceae *Portulaca oleracea L.: E28892 Talinum rugospermum Holz.: P32558 Primulaceae Lysimachia lanceolata Walt.: P32492 Lysimachia quadriflora Sims: P32465 Lysimachia thyrsiflora L.: P34975 Ranunculaceae Anemone canadensis L.: P31591 Anemone cylindrica Gray: P32617 Anemone virginiana L.: P34680 Caltha palustris L.: P31590 Ranunculus abortivus L.: P31509 Ranunculus longirostris Godr.: P31658 Ranunculus pensylvanicus L. f.: E28898 Ranunculus sceleratus L.: P32685 Thalictrum dasycarpum Fisch. & Lall. var. hypoglaucum (Rydb.) Boivin: P31556 Rhamnaceae *Rhamnus cathartica L.: P32647 Rosaceae Agrimonia parviflora Sol.: E28893 Crataegus mollis (Torr. & Gray) Scheele: P31631 Fragaria virginiana Duchesne: P31477 Geum canadense Jacq.: P31664 Geum laciniatum Murr.: P31700 Malus ioensis (Wood) Britt.: P31632 *Malus pumila Mill.: P31502 Physocarpus opulifolius (L.) Maxim.: P31709 *Potentilla argentea L.: P31517 Potentilla arguta Pursh: E28924 *Potentilla norvegica L.: P32505 *Potentilla recta L.: P31649 Vascular Plant Communities of the Green River Lowlands in Northwestern IllinoisOctober 2009 77 Potentilla simplex Michx.: P31489 Prunus americana Marsh. var. americana: P31543 Prunus angustifolia Marsh.: P32493 Prunus pensylvanica L. f.: P35671 Prunus serotina Ehrh.: P31487 Prunus virginiana L.: P31521 *Rosa arkansana Porter: P32553 *Rosa damascena Mill.: P35671 Rosa carolina L.: P31594 *Rosa multiflora Thunb.: P31606 *Rosa spinosissima L.: P35670 Rubus allegheniensis Porter: P31623 Rubus flagellaris Willd.: P31600 Rubus occidentalis L. Bailey: P31534 Rubus pensilvanicus Poir.: P32498 Spiraea alba DuRoi: P32432 Rubiaceae Diodia teres Walt.: E28954 Galium aparine L.: P31493 Galium obtusum Bigel.: P31688 *Galium pedemontanum (Bellardi) All.: P35653 Galium tinctorium L.: P32452 Galium triflorum Michx.: P31661 Rutaceae Ptelea trifoliata L.: E28902 Salicaceae Populus deltoides Marsh.: P31716 Populus grandidentata Michx.: P32677 Populus tremuloides Michx.: P32548 Salix amygdaloides Anderss.: P31548 Salix discolor Muhl.: P32475 *Salix fragilis L.: P32523 Salix humilis Marsh.: P32550 Salix interior Rowlee: P31547 Salix nigra Marsh.: P32620 Santalaceae Comandra umbellata (L.) Nutt.: P31510 Saxifragaceae Heuchera richardsonii R. Br.: P31693 Penthorum sedoides L.: P32359 Saxifraga pensylvanica L.: P31586 Scrophulariaceae Agalinis purpurea (L.) Pennell: P32470 Agalinis tenuifolia (Vahl) Raf.: P32472 Chelone glabra L.: P32513 Gratiola neglecta Torr.: P35669 Leucospora multifida (Michx.) Nutt.: P32536 Lindernia anagallidea (Michx.) Pennell: P32416 Mimulus ringens L.: P32502 Nuttallanthus canadensis (L.) D. Sutton: P31532 Pedicularis lanceolata Michx.: P32433 Penstemon pallidus Small: P31528 Scrophularia lanceolata Pursh: P31626 Vol. 39 Art. 278 Illinois Natural History Survey Bulletin *Verbascum thapsus L.: E28903 *Veronica arvensis L.: P31514 Veronica peregrina L.: P31515 Veronicastrum virginicum (L.) Farw.: E28927 Solanaceae *Datura stramonium L.: P32649 Physalis subglabrata Mack. & Bush: P32659 Physalis virginiana Mill.: P31596 Solanum carolinense L.: P32404 *Solanum dulcamara L.: P31691 Solanum ptychanthum Dunal: E28889 Ulmaceae Celtis occidentalis L.: P32388 Ulmus americana L.: P32525 *Ulmus pumila L.: P32401 Ulmus rubra Muhl.: P31620 Urticaceae Boehmeria cylindrica (L.) Sw.: E28921 Parietaria pensylvanica Muhl.: P31616 Pilea pumila (L.) Gray: P32528 Urtica gracilis Ait.: E28920 Verbenaceae Phyla lanceolata (Michx.) Greene: P32535 Verbena bracteata Lag. & Rodr.: P31603 Verbena hastata L.: E28939 Verbena stricta Vent.: E28904 Verbena urticifolia L.: P32547 Violaceae Viola affinis LeConte: P31503 Viola lanceolata L.: P31506 Viola pedata L.: P31531 Viola pratincola Greene: P32579.1 Viola pubescens Ait.: P34611 *Viola rafinesquei Greene: P31522 Viola sagittata Ait.: P31472 Viola sororia Willd.: P32579.2 Vitaceae Parthenocissus inserta (Kern.) K. Fritsch: P32396 Parthenocissus quinquefolia (L.) Planch.: P32543 Vitis riparia Michx.: P31621 Zygophyllaceae Tribulus terrestris L.: P34693 University of Illinois Institute of Natural Resource Sustainability William Shilts, Executive Director Illinois Natural History Survey Brian D. Anderson, Director Forbes Natural History Building 1816 South Oak Street Champaign, Illinois 61820 217-333-6880 ISBN 978-1-882932-23-8 Untitled-12 1 9/2/09 9:59:49 AM