Abstract: Microtropis macrocarpa Cheng & Kao has been treated as a synonym of M. macrophylla Merrill & Freeman in most taxonomic literature in China. According to our study, M. macrocarpa Cheng & Kao is an independent species endemic to Yunnan, China. M. macrophylla Merrill & Freeman and M. pachyphylla Merrill & Freeman should be treated as synonyms of M. longifolia Wallich ex Kurz. M. macrocarpa Cheng & Kao is also identified as an critically endangered species-CR B1ab (i,ii,iii,v) based on the IUCN Red List Categories and Criteria. The foliar surface, anther and pollen structures were also observed with SEM.