Pterocymbium R. Br ( Malvaceae , Sterculioideae ), a genus new to China

Abstract

[ Objective ] The present study reports a newly recorded giant tropical deciduous tree , Pterocym- bium macranthum Kosterm. , which has been spotted in the border regions of Sino-Lao , Mengla County , Yunnan Province , and both the species and genus are new to China. Furthermore , descriptions of the spe- cies and genus are amended , and the domestic population size and state of endangerment are evaluated. [ Methods ] Morphological and anatomical observations of specimens were conducted using a stereo- microscope , and key taxonomic characteristics were recorded with a digital camera. Aided by drones , its domestic population size was assessed , and its IUCN species threat level was evaluated by interviews and our field experiences. [ Results ] Around 1 000 individuals were recognized in an area ca. 2 000 hm 2 , and it was recommended as an IUCN vulnerable ( VU ) species. [ Conclusion ] The genus Pterocymbium R. Br. and its intragenus P . macranthum Kosterm. are new to China. The new discovery in China extends the known geographical range of P . macranthum to the northern edge of the Asian tropics and contributes to the knowledge of the flora both in China and Southeast Asia.

Keywords

• pterocymbium
• malvaceae
• biogeography
• indo-burma biodiversity hotspot
• transboundary biodiversity conservation