Gymnema wiyadae (Apocynaceae: Asclepiadoideae), a new species from eastern Thailand

Abstract

Gymnema wiyadae A.Kidyoo, recently discovered in eastern Thailand, is here described and compared with the morphologically similar species, G. inodorum (Lour.) Decne. and G. foetidum Tsiang. These three species are characterised by umbelliform cymes with subhypocrateriform, yellow flowers and corolline corona of five longitudinal ridges with lines of stiff golden-brown trichomes running along two sides. Gymnema wiyadae is, however, clearly distinguished from the other two species by its pubescent stem and branches with trichomes arranged in two rows, stout peduncles and pedicels, and style-head with obtuse apex. Illustrations and photographs of the new species as well as an updated identification key for all known species of Gymnema R.Br. occurring in Thailand are provided.