(Annonaceae): a new species from Surat Thani Province, Peninsular Thailand.

A new species, R.M.K.Saunders & Chalermglin, (Annonaceae), is described from Surat Thani Province in Peninsular Thailand. It resembles two other species, Ridl. and Ridl., with which it is broadly sympatric, but can be distinguished by its solitary flowers (not borne in thyrsoid inflorescences as in most other species), single carpel per flower (and hence single monocarp per fruit) and the lack of a monocarp stipe. A key to the nine species in Thailand is provided.