Microsoft Word - 07. Rhododen 2nd Proof.doc Bangladesh J. Plant Taxon. 22(2): 119-123, 2015 (December) RHODODENDRON LEIGONGSHANENSE (ERICACEAE), A NEW SPECIES FROM CHINA CHENG-HUA YANG, ZHENG-GUO XIE1, YONG-FU YU1 AND ZHI-RONG YANG2 Forestry Academy of Guizhou Province, Guiyang 550005, Guizhou, People’s Republic of China Keywords: China; Ericaceae; New species; Rhododendron. Abstract Rhododendron leigongshanense, a new species from Leishan County, Guizhou Province, China, is described and illustrated. The new species is close to R. magniflorun W.K. Hu and R. glanduliferum Franchet, but differs by having stipitatus glands on leaf abaxial surface, corolla trumpet-shaped with 7 lobes, 7.5–8.0 cm long, 8–10 cm in diameter and calyx 7- lobed. Introduction The genus Rhododendron L. is one of the largest genera of the family Ericaceae with many ornamental species with high horticultural value (Fang, 1999). The genus consists of about 1000 species and is distributed in Asia, Europe and North America. So far, 574 species have been recorded in China, of which 409 are endemic (Fang et al., 2005). The southwest-central region of China, including Guizhou Province is possibly the region of the geographic origin of the genus Rhododendron (Fang and Ming, 1995). Leigongshan National Nature Reserve is located at southeast Guizhou Province, China, which has rich natural plant resources, including approximately 24 species of Rhododendron. In 2011 and 2012, the authors conducted an intensive taxonomic survey of Rhododendron in this area, when a previously unknown specimen belonging to Rhododendron was found. The plant grew in evergreen broad-leaved forests on limestone hills (latitude 26°21′50″N, longitude 108°08′29″E) at an altitude of 1,400 m. After critical examination of herbarium specimens from GF, HGAS, GZAC and PE herbaria and carefully consulting relevant literature (Zhou and Yao, 1989; Zhang and Chen, 1990; Hu and Fang, 1994; Fang et al., 1999; Fang et al., 2005; Zhang and Zhang, 2007; Chen et al., 2010a, b; Chen et al., 2012; Yang et al., 2012 ), this species was very distinct when compared with its morphologically closest matches. Thus it is described and illustrated herein as Rhododendron leigongshanense sp. nov. Rhododendron leigongshanense C.H. Yang, Z.G. Xie, Y.F. Yu & Z.R. Yang, sp. nov. (Figs 1& 2). Diagnosis: The new species is morphologically similar to R. magniflorum and R. glanduliferum, but differs by its leaf abaxial surface with stipitatus glands, corolla trumpet-shaped with 7 lobes, 7.5–8.0 cm long, 8–10 cm in diameter, and calyx 7-lobed. More detailed morphological differences among these three species are given in Table 1. Types: China. Guizhou: Leishan County, Leigongshan National Nature Reserve, Huxiongpo, 26°21′50″N, 108°08′29″E, altitude 1400 m, 25 June 2012, Chenghua Yang 7590 (fl) (Holotype: GF; Isotypes: HGAS, PE). 1Administrative Bureau of Leigongshan National Nature Reserve, Leishan 557100, Guizhou, People’s Republic of China. 2Corresponding author. State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People’s Republic of China. Email: zry@ibcas.ac.cn 120 YANG et al. Paratypes: China. Guizhou: Leishan County, Leigongshan National Nature Reserve, Huxiongpo, 3 July 2011, Chenghua Yang & Zhengguo Xie 7667 (fl) (GF); ibid. 8 July 2011, Chenghua Yang & Zhengguo Xie 7751 (GF); ibid. 8 September 2011, Chenghua Yang & Yongfu Yu 9232 (fr.) (GF). Fig. 1. Rhododendron leigongshanense C.H. Yang, Z.G. Xie, Y.F. Yu & Z.R. Yang, sp. nov. A. Flowering branch; B. Corolla (displaying); C. Leaf blade (adaxial surface); D. Capsule; E. Ovary (ampliate); F. Leaf blade abaxial surface (ampliate). RHODODENDRON LEIGONGSHANENSE SP. NOV. (ERICACEAE) 121 Fig. 2. Rhododendron leigongshanense C.H. Yang, Z.G. Xie, Y.F. Yu & Z.R. Yang, sp. nov. A. Habitat and habit; B. Leaf blade showing stipitatus glands on leaf abaxial surface; C. Flower, showing trumpet- shaped corolla with 7 petals; D. Capsule. Table 1. Comparison of morphological characteristics among Rhododendron leigongshanense sp. nov., R. magniflorum and R. glanduliferum. Characters R. leigongshanense sp. nov. R. magniflorum R. glanduliferum Leaf blade Oblong-elliptic Oblong Oblong-lanceolate or oblanceolate Leaf surface Abaxial surface stipitate, glandular-hairy Abaxial surface smooth Abaxial surface smooth Lobes of calyx 7 5 7 or 8 Lobes of corolla 7 5 7 or 8 Corolla size 7.5–8.0 cm long 9.5–10.0 cm long 5–6 cm long Corolla shape Trumpet shaped Tabulate - funneliform Funneliform - campanulate 122 YANG et al. Evergreen small tree, 5 m tall, c. 16 cm in diameter; branchlets thick, cylindrical with stipitate glands. Leaf blade leathery or thick-leathery, 6–9 leaves on branch-top, pendulous; young leaves violet, densely stipitate glands and floccose; leaf blade oblong-elliptic, apex acute, base broadly cuneate, slightly asymmetry, 15–21 × 5.0–7.5 cm, margin revolute, abaxial surface stipitate glands; midrib, veins and lateral veins slightly grooved adaxially, midrib and lateral veins prominent abaxially, lateral veins 15–18 pairs. Petiole 2–4 cm long, glandular. Inflorescence racemose, 10 or 11-flowered, rachis light brown, 7.0–9.5 cm long, densely stipitate glands; bract lanceolate, abaxial thinly stipitate or non-stipitate glands, adaxial densily glands and villous; pedicels 3.5–4.5 cm long with densely long glands. Calyx 7-lobed, lobes semi-circle, disparate, 2– 4 mm long, abaxial glandular, adaxial smooth. Corolla trumpet-shaped, 7-lobed, white, 7.5–8.0 × 8.0–10.0 cm, succulent, aromatic, rotund, abaxial stipitate or non-stipitate glands. Stamens 16, unequal, 4–6 cm long, filaments bald. Ovary conoid, 5–8 mm long, densely glands; style thick, 5– 8 cm long, faint green, densely stipitate or non-stipitate glands to the tip; stigma pale, disk-like, 2– 3 mm in diameter. Capsule cylindric, 3.0–3.5 × 1.0–1.2 cm, slightly curved, densely stipitate or non-stipitate glands. Phenology: Flowering from June to July; fruiting from October to November. Etymology: The specific epithet is named after the type locality Leigongshan. Vernacular name: Leigongshan Dujuan. Distribution: So far, this species is only known from the type locality Leigongshan Nature Reserve, Leishan County, Guizhou Province, southwest China. Habitat: This species grows in evergreen broad-leaved forests on limestone hills at 1,400 m. IUCN Red List category: Since only one population and a total of 50 mature individuals of this species were found in the area from where the type collections were made, the species seems to be very rare and restricted in distribution. A preliminary conservation assessment for the species gave it Critically Endangered (CR) status, based on criterion D (population less than 50 mature individuals) of the IUCN Red List criteria (IUCN, 2011). Therefore, careful protection of the species is warranted. Acknowledgements This work was supported by the National Natural Science Foundation of China (grant no. 31370657), through the projects 'Study on Magnoliaceae Plant in Guizhou' and 'Study on Wetland Plant in Guizhou'. The authors are grateful to curators of the herbaria GF, HGAS, GZAC and PE for allowing them to access their collections. They also thank Prof. Rui-Zheng Fang for revising the morphological description, Prof. Zu-Pei Liu for revising the English and Mr. Hua Xie for preparing the original line drawings. The authors also appreciate the support given by Administrative Bureau of Leigongshan National Nature Reserve and the assistance rendered by Xiao-Yong Dai and Yun-Li Jiang during fieldwork. References Chen, X., Laurie, C., Huang, J.Y. and Chen, X. 2010a. New taxa of Rhododendron (Ericaceae) from China. Ann. Bot. Fennici. 47: 397−402. Chen, X., Huang, J.Y., Laurie, C. and Chen, X. 2010b. Two new species of Rhododendron (Ericaceae) from Guizhou, China. Novon 20(4): 386−391. Chen, X., Yang, C.H., Xie, H. and Chen, X. 2012. A new species of Rhododendron (Ericaceae) from China. J. Trop. Subtrop. Bot. 20(5): 513−516. [In Chinese]. Fang, M.Y., Fang, R.C., He, M.Y., Hu, L.Z., Yang, H.B. and Chamberlain, D.F. 2005. Rhododendron. In: Wu, Z.Y. and Raven, P.H. (Eds), Flora of China, Vol. 14. 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