Tuesday, September 3, 2019

[Botany • 2019] Marsdenia yarlungzangboensis (Apocynaceae: Asclepiodoideae) • A New Species from Xizang, China


Marsdenia yarlungzangboensis C.Liu, J.D.Ya & Y.H.Tan

in Liu, Ya, Tan, et al, 2019. 

Abstract
Marsdenia yarlungzangboensis (Apocynaceae, Asclepiadoideae), a new species from Motuo County, southeastern Xizang of China, is described and illustrated. It is morphologically similar to M. medogensis, M. tenii and M. yuei, the major differences between the new species and the morphological relatives are outlined and discussed. A diagnostic key to the new species and its closely related species in China is provided.

Keywords: Marsdenia, Marsdenia yarlungzangboensis, new species, China

Figure 1. Marsdenia yarlungzangboensis C.Liu, J.D.Ya & Y.H.Tan
A habit B flower (lateral view) C opened calyx D opened corolla E gynostegium and staminal corona F pistil G pollinarium. 

Figure 2. Marsdenia yarlungzangboensis C.Liu, J.D.Ya & Y.H.Tan 
A habit B inflorescences and adaxial leaf surface C abaxial leaf surface D flower (lateral view) E flower (front view, showing hairy throat) F opened corolla G opened calyx H gynostegium and staminal corona I pistil J pollinarium. 
Photos: Cheng Liu (A–E) and Lian-Yi Li (F–J).



Marsdenia yarlungzangboensis C.Liu, J.D.Ya & Y.H.Tan, sp. nov.


Diagnosis: Marsdenia yarlungzangboensis is morphologically similar to M. medogensis, M. tenii and M. yuei, but differs from M. medogensis in inflorescences pubescent; sepals suborbicular; corolla yellow, throat red and densely pilose, shorter lobes and reddish outside, apex emarginate, margin reddish and ciliate; corona lobes triangular, to base of anthers; stigma head hemispherical; and differs from M. tenii in leaf blades elliptic; sepals suborbicular; corolla yellow, throat red, lobes reddish outside, margin reddish; stigma head hemispherical, conspicuously exserted from anther appendages and corolla tube; and also differs from M. yuei in leaf blades elliptic; inflorescences unbranched and pubescent; sepals suborbicular; corolla yellow, throat red and densely pilose; lobes ovate, apex emarginate; corona lobes to base of anthers.
....

Distribution and habitat: Marsdenia yarlungzangboensis grows at the margins of subtropical evergreen broad-leaved forest with main community types of Castanopsis echinocarpa J. D. Hooker & Thomson ex Miquel and Quercus gambleana A. Camus, Renqinbeng, Motuo County, Xizang, China, at an elevation of 1800–2100 m.

Etymology: The specific epithet ‘yarlungzangboensis’ is derived from the type locality, Yarlung Zangbo Grand Canyon, Motuo County, southeast Xizang, China.

Vernacular name: Yǎ Lǔ Zàng Bù Niú Nǎi Cài (Chinese pronunciation); 雅鲁藏布牛奶菜 (Chinese name).


 Cheng Liu, Ji-Dong Ya, Yun-Hong Tan, Hua-Jie He, Gui-Jun Dong and De-Zhu Li. 2019. Marsdenia yarlungzangboensis (Apocynaceae, Asclepiadoideae), A New Species from Xizang, China. PhytoKeys. 130: 85-92. DOI: 10.3897/phytokeys.130.34152