{"paper_id":"6aedac38-662c-45b1-9cd1-9b3e8ad90256","body_text":"PREPRINT\nAuthor-formatted, not peer-reviewed document posted on 08/03/2024\nDOI: https://doi.org/10.3897/arphapreprints.e122409\nA new synonym of Rhododendron subgenus \nHymenanthes (Ericaceae)\nSheng Chen, Lei Hao, Jun-Mei Yuan,  Jia-Xin Lou, Yun-Song Lou, Xiang Chen\n\nA new synonym of Rhododendron subgenus Hymenanthes (Ericaceae) \n \nSheng Chen1, Lei Hao1, Jun-Mei Yuan1, Jia-Xin Lou1, Yun-Song He1, Xiang Chen1* \n1 Institute of Biology, Guizhou Academy of Sciences, Guiyang 550009, China \n \n* Corresponding author: Xiang Chen (xiangchengz@163.com) \n \nAbstract \nMorphological comparison indicate s that Rhododendron oligocarpum is \nconspecific with R. leishanicum. Therefore, we reduced R. oligocarpum to a synonym \nof R. leishanicum.  \n \nKeywords \nRhododendron, Rhododendron leishanicum, morphology, new synonym \n \nRhododendron L. is the largest genus of Ericaceae, which c ontains ca. 1200 \nspecies (Chamberlain et al. 1996; MacKay and Gardiner 2017). This genus is widely \ndistributed the Asia, Europe and North America, of which the great majority occurs in \nChina and the Malaysian archipelago, the centers of diversity are in the Himalayas and \nSouth East Asia  (Fang et al . 2005; Gibbs et al . 2011). When we revised the type \nspecimens of Rhododendron from Guizhou Province, China, R. leishanicum Fang et S. \nS. Chang ex Chamb.  and R. oligocarpum  Fang et X. S. Zhang  were found to be \nmorphologically very similar and identified very confusing. \nRhododendron leishanicum was originally described by Chamberlain  (1982) \nbased on a single collection, Austro-Guizhou Exped 909 , from Leigong mountain in \nLei Shan Xian, Guizhou Province, China  (Fig. 1A). In the protologue, Chamberlain \nplaced R. leishanicum in the Subsection Williamsiana. The next year, R. oligocarpum \nwas described by Fang (1983) based on six collections  (including Z. S. Zhang et al \n401557 (Typs), Z. S. Zhang 58, T. H. Tu 31739, from Fanjing Mountain ; Austro-\nGuizhou Exped 1411, from Leigong Mountain ; G. Z. Li 6211 & 11277, from Maoer \nMountain) from three different origins in China (Fig. 1B-D). According to the \nprotologue, Fang placed R. oligocarpum in the Subsection Maculifera. Meanwhile, R. \nleishanicum was again described as a new species by Fang in the same protologue. It is \nworth noting that a paratype of R. oligocarpum , Austro -Guizhou Exped 1141,  was \ncollected from Leigong Mountain  (Fig. 1C) , but the relationship between R. \noligocarpum and R. leishanicum were not mentioned in the protologue. \nAccording to critical examination of the type specimens and original descriptions \nof R. leishanicum and R. oligocarpum , we found that both species have tomentose \nyoung branches and petioles, with small apiculate leathery leaves, racemose-umbellate \ninflorescences, campanulate corolla, filaments pubescent at base, ovoid ovaries (Table \n1). Therefore, we place R. oligocarpum in synonymy with R. leishanicum according to \nICN rules (Turland et al. 2018). \n \nTaxonomy treatment \nAuthor-formatted, not peer-reviewed document posted on 08/03/2024. DOI:  https://doi.org/10.3897/arphapreprints.e122409\n\nRhododendron leishanicum Fang et S. S. Chang ex Chamb. (1982: 261). \nType:—CHINA. Guizhou province: Leishan Xian, L eishan, 1850 m, 29 april 1959, \nAustro-Guizhou Exped 909 (holotype: SZ; isotype: HGAS007912!; KUN0540381!). \nRhododendron oligocarpum Fang et X. S. Zhang (1983: 466). syn. nov. \nType: —CHINA. Guizhou province: Yinjiang county, Sanduodian, 2070 m, 14 april \n1964, Z. S. Zhang et al 401557  (holotype: HGAS0088928!; isotypes: IBSC0481928!; \nPE01297915!, PE01297916! ; paratype: HGAS007915!; IBK00187538!; \nIBK00187539!; IBK00187541!; IBK00187559!; PE00312607!; PE00313389!; \nKUN540382!; SZ0036179!). \n \nDescription. Shrubs or small trees, 3 -6 m tall; bark gray, dehiscent on drying; \nbranchlets terete, 3 -4 mm in diam., setose when young, grad -ually glabrescent; bud \nscales membranous, long-ovate, 1-1.5 ×  0.5-0.7 cm, apex rounded or with short cusp, \nwith yellowish hairs on outer surface, inner surface glabrous. Petiole rounded abaxially, \nfurrowed adaxially, 5-15 mm, densely setose; leaf blade leathery, elliptic or obovate, 4-\n6 ×  2-3 cm; base rounded or subcordate; margin revolute, apex rounded, with small \napiculate; abaxial surface pale green, glabrous or sometimes sparsely hairy on midrib; \nadaxial surface green, sparsely glandular; midrib impressed abaxially, grooved \nadaxially; lateral veins 11 -15-paired, inconspicuous on both surfaces.  Inflorescence \nracemose-umbellate, 3-5-flowered; rachis 5-7 mm, tomentose. Pedicel 1-2 cm, densely \nsetose-tomentose; calyx teeth 5, 1 -2 mm; corolla campanulate, purple -red, with deep \npurple basal spots, 3 -3.5 cm, lobes 5, sub -orbicular, ca. 1.5 × 2 cm; apex emarginate; \nstamens 10, unequal, 1–2 cm, filaments pubescent at base, ovary cone-shaped, 4-5 mm, \ndensely setulose -tomentose; style 2.5 -3 cm, glabrous, stigma slightly expanded. \nCapsule cylindric, 20-25 ×  ca. 7 mm, rough. Flowering from April to May and fruiting \nfrom September to October. \n \nDistribution and habitat. Rhododendron leishanicum  is distributed in  Eastern \nGuizhou and Northeastern Guangxi. It grows in Thickets at 1800-2500 m a.s.l. \n \nSpecimens examined. China. Guizhou: Qiandongnan Prefecture, Leigong Mountain, \nP . L. Song 1016 (GYBG barcode 0002282, 0002283), 4407 (CCNU barcode 9018123), \n4717 (CCNU barcode 9018122); Tongren City, Fanjing Mountain, Z. S. Zhang et al \n401673 (IBSC barcode 0481934), 401317 (HGAS barcode 0088940, IBSC barcode \n0481929), 400681 (HGAS barcode 0088933), 400610 (HGAS barcode 0088939), Z. P . \nJian 32039 (HGAS barcode 0088938), Wuling Mountain Expedition 731 (GFS barcode \n0007355, KUN barcode 0339467, 0339468, PE barcode 00258535), 1348 (GFS \nbarcode 0007356, KUN barcode 0339469). Guangxi: Guilin City, Maoer Mountain, G. \nZ. Li 11272  (IBK barcode 00187540), 12378 (IBK barcode 00187542), 12084 (IBK \nbarcode 00187561), F . X. Jin 1066 (HTC barcode 0010523, 0010524, 0010525), J. X. \nZhong 83311 (IBK barcode 00187551, 00187552, IBSC barcode 0481913), 83523 (IBK \nbarcode 00187560), 81647 (IBK barcode 00187566, 00187567), L. M. Gao 20077  \n(KUN barcode 0767388, 0767389). \n \nAuthor-formatted, not peer-reviewed document posted on 08/03/2024. DOI:  https://doi.org/10.3897/arphapreprints.e122409\n\nAcknowledgements \nWe thank the curators of PE, IBSC, KUN, IBK, SZ and HGAS for allowing  us to \nexamine specimens or use images of specimens and the National Specimen Information \nInfrastructure (NSII , https://www. nsii.org.cn/2017/) for availability of digitized \nspecimens. \n \nAdditional information \nConflict of interest \nThe authors have declared that no competing interests exist. \n \nEthical statement \nNo ethical statement was reported. \n \nFunding \nThis study was supported by Young Scientists Fund of Guizhou Academy of Sciences \n(Qiankeyuan Key -J [2024] 15) and National Natural Science Foundation of China \n(31160037) and Guizhou Provincial Basic Research Program  (Natural Science)-Study \non the Type Specimens of Vascular Plants in Guizhou Based on DELTA System \n(Qiankehe Fundamentals-ZK [2023] General 234). \n \nAuthor contributions \nConceptualization: XC, LH, SC. Data curation: JMY, JXL, YSH . Writing – original \ndraft: SC, LH, XC. Writing - review and editing: SC, XC. \n \nAuthor ORCIDs \nSheng Chen https://orcid.org/0000-0002-2727-6504 \nLei Hao https://orcid.org/0009-0001-0276-6523 \nJun-Mei Yuan https://orcid.org/0009-0007-1861-5790 \nJia-Xin Lou https://orcid.org/0009-0005-9845-1655 \nYun-Song He https://orcid.org/0009-0002-8791-558X \nXiang Chen https://orcid.org/0009-0008-0773-4978 \n \nData availability \nAll of the data that support the findings of this study are available in the main text. \n \nReferences \nChamberlain DF (1982) A Revision of Rhododendron II. Subgenus Hymenanthes. \nNotes from The Royal Botanic Garden Edinburgh, 39(2):209–486. \nChamberlain DF, Hyam R, Argent G , Fairweather G , Walter KS (1996) The Genus \nRhododendron: Its Classification and Synonymy. Royal Botan ic Garden \nEdinburgh, Edinburgh, 181. \nFang WP  (1983) New taxa of the genus Rhododendron from China. Acta \nPhytotaxonomica Sinica, 21(4): 457–469. \nFang MY , Fang RZ, He MY , Hu LZ, Yang HB, Chamberlain, DF (2005) Rhododendron. \nAuthor-formatted, not peer-reviewed document posted on 08/03/2024. DOI:  https://doi.org/10.3897/arphapreprints.e122409\n\nIn: Flora of China. vol. 14. . Science Press, Beijing & Missouri Botanical Garden \nPress, St. Louis, 260–373. \nFranchet MA (1895) Plantes Nouvelles de la Chine Occidentale. Journal de Botanique, \n9: 393. \nGibbs D, Chamberlain DF, Argent G (2011) The Red List of Rhododendrons. Botanic \nGardens Coservation International, Richmond, 4–11. \nMacKay ., Gardiner SE (2016) A model for determining ex situ conservation priorities \nin big genera is provided by analysis of the subgenera of Rhododendron \n(Ericaceae). Biodivers Conserv, 26(1): 189–208. \nhttps://doi: 10.1007/s10531-016-1237-0 \nTurland NJ, Wiersema JH, Barrie FR, Greuter  W, Hawksworth DL, Herendeen PS, \nKnapp S, Kusber WH, Li DZ, Marhold K, May TW, McNeill J, Monro AM, Prado \nJ, Price MJ, Smith GF (2018) International Code of Nomenclature for algae, fungi, \nand plants (Shenzhen Code) adopted by the Nine teenth International Botanical \nCongress Shenzhen, China, July 2017. Regnum Vegetabile 159. Koeltz Botanical \nBooks, Glashü tten. \nhttps://doi.org/10.12705/Code.2018 \n \nAuthor-formatted, not peer-reviewed document posted on 08/03/2024. DOI:  https://doi.org/10.3897/arphapreprints.e122409","source_license":"CC-BY-4.0","license_restricted":false}