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Corresponding author: Xiang Chen ( xiangchengz@163.com ) Academic editor: Bing Liu
© 2024 Sheng Chen, Lei Hao, Yi-Hui Deng, Cheng-Hua Yang, Jun-Mei Yuan, Jia-Xin Lou, Yun-Song He, Xiang Chen.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Chen S, Hao L, Deng Y-H, Yang C-H, Yuan J-M, Lou J-X, He Y-S, Chen X (2024) A new synonym of Rhododendron leishanicum (subg. Hymenanthes) from China (Ericaceae). PhytoKeys 243: 9-14. https://doi.org/10.3897/phytokeys.243.121263
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Based on a critical examination of type specimens, images of living plants, and the literature has shown Rhododendron oligocarpum to be conspecific with R. leishanicum. Although slight variations in corolla colour exist amongst different populations of R. oligocarpum, it does not serve as a key distinguishing trait. Therefore, we reduced R. oligocarpum to a synonym of R. leishanicum, and recommend placing it in Subsection Maculifera.
Morphology, new synonym, Rhododendron, Rhododendron leishanicum
Rhododendron L. which contains ca. 1200 species, is the largest genus of Ericaceae (
Rhododendron leishanicum was originally described by
According to critical examination of the type specimens and morphological comparisons of R. leishanicum and R. oligocarpum, we found that both species have setose young branches and petioles, with small apiculate leathery leaves, racemose-umbellate inflorescences, corolla campanulate, with deep purple basal spots, pedicel, ovary and filament with identical indumentum (Fig.
Comparison of Rhododendron leishanicum and R. oligocarpum A, D, G, J, M R. leishanicum from Leigong mountain B, E, H, K, N R. oligocarpum from Fanjing mountain C, F, I, L, O R. oligocarpum from Maoer mountain A–C branchlets with flowers D–F adaxial and abaxial surface of leaf G–I corolla with deep purple basal spots J–L pedicel, Calyx, ovary and style indumentum M–O stamens side view.
Based on the setose branchlets and petioles, the small apiculate leaves, the campanulate corolla and the glabrous style, we suggest placing R. leishanicum in the Subsection Maculifera.
China. Guizhou province: Leishan Xian, Leishan, 1850 m elev, 29 April 1959, Austro-Guizhou Exped 909 (holotype: SZ; isotype: HGAS007912!; KUN0540381!).
China. Guizhou province: Yinjiang county, Sanduodian, 2070 m elev, 14 april 1964, Z. S. Zhang et al. 401557 (holotype: HGAS0088928!; isotypes: IBSC0481928!; PE01297915!, PE01297916!; paratype: HGAS007915!; IBK00187538!, IBK00187539!, IBK00187541!, IBK00187559!; PE00312607!, PE00313389!; KUN540382!; SZ0036179!).
Shrubs or small trees, 3–6 m tall; bark grey, dehiscent on drying; branchlets terete, setose when young, gradually glabrescent. Petiole rounded abaxially, furrowed adaxially, 5–15 mm, densely setose; leaf blade leathery, elliptic or obovate, 4–8 × 2–4 cm; base rounded or subcordate; margin revolute, apex rounded, with small apiculate; adaxial surface green, abaxial surface pistachio; mid-rib impressed abaxially, grooved adaxially, glabrous or sometimes sparsely hairy; lateral veins 11–15-paired, slightly conspicuous on both surfaces. Inflorescence racemose-umbellate, 3–5-flowered; rachis 5–7 mm, tomentose. Pedicel 1–2 cm, densely setose-tomentose; Calyx small, discoid, lobes 5, triangular, tomentose, 1–2 mm. Corolla campanulate, purple-red to rose-red, with deep purple basal spots, 3–3.5 cm; lobes 5, suborbicular, ca. 1.5 × 2 cm, apex emarginate; stamens 10, unequal, 1–3 cm, filaments puberulent at base; ovary cone-shaped, 4–5 mm, densely densely setose and tomentose; style 2.5–3 cm, glabrous, stigma slightly expanded. Capsule cylindrical, 20–25 × 7 mm, rough. Flowering from April to May and fruiting from September to October.
Rhododendron leishanicum is distributed in Eastern Guizhou and North-eastern Guangxi. It grows in Thickets at 1800–2500 m a.s.l.
China. Guizhou: Qiandongnan Prefecture, Leigong Mountain, P. L. Song 1016 (GYBG barcode 0002282, 0002283), 4407 (CCNU barcode 9018123), 4717 (CCNU barcode 9018122); Tongren City, Fanjing Mountain, Z. S. Zhang et al. 401673 (IBSC barcode 0481934), 401317 (HGAS barcode 0088940, IBSC barcode 0481929), 400681 (HGAS barcode 0088933), 400610 (HGAS barcode 0088939), Z. P. Jian 32039 (HGAS barcode 0088938), Wuling Mountain Expedition 731 (GFS barcode 0007355, KUN barcode 0339467, 0339468, PE barcode 00258535), 1348 (GFS barcode 0007356, KUN barcode 0339469). Guangxi: Guilin City, Maoer Mountain, G. Z. Li 11272 (IBK barcode 00187540), 12378 (IBK barcode 00187542), 12084 (IBK barcode 00187561), F. X. Jin 1066 (HTC barcode 0010523, 0010524, 0010525), J. X. Zhong 83311 (IBK barcode 00187551, 00187552, IBSC barcode 0481913), 83523 (IBK barcode 00187560), 81647 (IBK barcode 00187566, 00187567), L. M. Gao 20077 (KUN barcode 0767388, 0767389).
We thank the curators of PE, IBSC, KUN, IBK, SZ and HGAS for allowing us to examine specimens or use images of specimens and the National Specimen Information Infrastructure (NSII, https://www.nsii.org.cn/2017/) for availability of digitised specimens.
The authors have declared that no competing interests exist.
No ethical statement was reported.
This study was supported by Young Scientists Fund of Guizhou Academy of Sciences (Qiankeyuan Key-J [2024] 15) and National Natural Science Foundation of China (31160037) and Guizhou Provincial Basic Research Program (Natural Science)-Study on the Type Specimens of Vascular Plants in Guizhou Based on DELTA System (Qiankehe Fundamentals-ZK [2023] General 234).
Conceptualisation: XC, LH, SC. Data curation: YHD, CHY, JMY, JXL, YSH. Writing – original draft: SC, LH, XC. Writing – review and editing: SC, XC.
Sheng Chen https://orcid.org/0000-0002-2727-6504
Lei Hao https://orcid.org/0009-0001-0276-6523
Yi-Hui Deng https://orcid.org/0009-0006-2821-0247
Chen-Hua Yang https://orcid.org/0000-0002-5941-676X
Jun-Mei Yuan https://orcid.org/0009-0007-1861-5790
Jia-Xin Lou https://orcid.org/0009-0001-0276-6523
Yun-Song He https://orcid.org/0009-0002-8791-558X
Xiang Chen https://orcid.org/0009-0008-0773-4978
All of the data that support the findings of this study are available in the main text.