Abstract
A new species, Maerua koratensis (Capparaceae), only known from a restricted locality in Nakhon Ratchasima Province, eastern Thailand, is here described and illustrated. This is the second species of Maerua to be described from South-East Asia. This new species is distinguished by the simple leaves, petaliferous flowers with distinctly 4-lobed laciniate disc, and cylindrical, torulose to moniliform fruits. Morphological characteristics of M. koratensis and M. juncea subsp. juncea, its most similar, are compared. A key to the Maerua species occurring in mainland South-East Asia is provided.