Apocynaceae subfamily Asclepiadoideae is one of the most derived plant groups, comprising about 164 genera with around 3000 species. Cynanchum was placed in subtribe Cynanchinae of tribe Asclepiadeae.
Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) collected an unknown species of Cynanchum in Menghai during their extensive botanical studies in Xishuangbanna.
After carrying out morphological studies and literature review, XTBG researchers confirmed that the flowering Cynanchum plant is new to science. They named it as Cynanchum brevipedunculatum to refer to its short peduncle and got it published in journal Taiwania.
Cynanchum brevipedunculatum is similar to C. decipiens and C. longipedunculatum, but has much bigger leaves, adaxially sparsely strigillose, abaxially glabrous or sparsely strigillose on the veins, and with a shorter peduncle.
Cynanchum brevipedunculatum is a twining plant, up to 4 meters high. Its peduncle is short (1.8–2.2 cm).
The species is currently known only from the type locality in Menghai (21°50′N, 100°7′E, altitude 1905 m) and found growing beside the road. Only one population with two individual plants was found even after carefully surveying its surrounding forests.
Based on the limited population size and restricted distribution of C. brevipedunculatum, the researchers assessed the species as Critically Endangered according the standard of IUCN.
Department of Gardening and Horticulture, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
Cynanchum brevipedunculatum A. Habit. B-C. Adaxial and abaxial leaf surface. D-E. Inflorescences and flowers. F. Gynostegium in side view. G. Gynostegium in top view. H. Pollinarium.
(Images by SHEN Jianyong)