A revision of Meiogyne (Annonaceae) in Thailand, with descriptions of four new species

We review the species diversity of the Asian genus Meiogyne (Annonaceae) in Thailand. Four new species, M. anomalocarpa, M. chiangraiensis, M. gardneri, and M. maxiflora, are described. Meiogyne anomalocarpa has the widest distribution of any Meiogyne species in Thailand, but the other three species are narrowly distributed. Meiogyne anomalocarpa and M. maxiflora have the axillary inflorescences typical of the genus, but in M. chiangraiensis and M. gardneri the inflorescences are flagelliform and arise from the lower trunk, a morphology previously unreported from members of this genus. The presence of M. chiangraiensis in northern Thailand extends the range of the genus significantly northward. Meiogyne caudata is reported as new to the flora of Thailand. Several Meiogyne specimens from southernmost Thailand previously identified as M. virgata in the past by various workers were found to be more similar to M. kanthanensis, recently described from Perak, Peninsular Malaysia. A key is provided for the eight species currently recognized as occurring in the country.