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| Argostemma ehuangzhangense H.G.Ye, Jia Liu & W.B.Liao, in Liu, Liu, Zhao, Fan, Ye, Wang & Liao, 2022. |
Abstract
Argostemma ehuangzhangense, a new Rubiaceae species from E’huangzhang Nature Reserve, Guangdong Province, China, is here described and illustrated. A morphological comparison between the new species and its putative relatives, A. lamxayanum, A. laotica and A. verticillatum, is presented. The new species is mostly similar to A. laotica, but they can be distinguished from each other since Argostemma ehuangzhangense presents solitary flower (vs. 2-flowered inflorescences), flower lobes 4 (vs. 5) and anthers opening by longitudinal slits (vs. apical pores). In a preliminary IUCN Red List status of Argostemma ehuangzhangense this species is assigned as Vulnerable (VU).
Keywords: Argostemma ehuangzhangense, China, Guangdong, new species, Rubiaceae
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| Argostemma ehuangzhangense A flower B fruit C style and stigma D habit of a mature plant E multicellular trichomes present on the stem, pedicel and ovary F corolla G organization of stamens H stamen (Drawn from living plants by Yun-Xiao Liu). |
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| Argostemma ehuangzhangense A individuals in their natural habitat B flowering individuals C fruiting individuals D side view of an individuals with tuber E leaf blade adaxial surface view F leaf blade abaxial surface view G flower, internal corolla surface view H folwer, external corolla surface view I capsule, top view J stamen K style and stigma tightly enclosed by stamens L ovary longitudinal section view. (photographs (A–G) were taken by Wan-Yi Zhao in the original habitat area of E’huangzhang and photographs (H–L) were taken by Jia Liu in SYS Herbarium in May 2018). |
Argostemma ehuangzhangense H.G.Ye, Jia Liu & W.B.Liao, sp. nov.
Diagnosis: Argostemma ehuangzhangense is similar to A. lamxayanum and A. laotica in its habit and pseudo-verticillate leaves, but differs in having terminal solitary 4-merous flowers, short anthers (1.2–1.5 mm long) opening by longitudinal slits.
Distribution: Argostemma ehuangzhangense is endemic to E’huangzhang Nature Reserve, southwestern Guangdong Province. It is currently known only from two populations recorded in county of Dianbai and city of Yangchun.
Habitat: Growing along river on wet sandstone under the evergreen broad-leaf forest at 400–750 m a.s.l.
Etymology: The specific epithet ‘ehuangzhangense’ is derived from the type locality, E’huangzhang Nature Reserve of the Guangdong Province, in China. This area is the oldest geological platform in the Guangdong Province, in which many endemic species occur (Wang et al. 2003; 2004; Ding et al. 2018). The new species is also expected to occur in the Yunkaishan National Nature Reserve, Maoming City, because this area shares a similar tectonic history with E’huangzhang. Therefore, we proposed for the vernacular name of the species as yuèxīxuěhuā (粤西雪花).
Zhong-Cheng Liu, Jia Liu, Wan-Yi Zhao, Qiang Fan, Hua-Gu Ye, Lei Wang and Wen-Bo Liao. 2022. Argostemma ehuangzhangense (Rubiaceae), A New Species from Guangdong, China. PhytoKeys. 214: 75-82. DOI: 10.3897/phytokeys.214.89276
