A taxonomic revision of Garcinia sections Dicrananthera and Macrostigma (Clusiaceae) in Thailand

<i>Garcinia</i> sections <i>Dicrananthera</i> and <i>Macrostigma</i> (Clusiaceae) is revised for Thailand. Three species are enumerated, i.e., one species, <i>G.thorelii</i> belongs to the sectionDicrananthera, and two species, <i>G.nuntasaenii</i> and <i>G.prainiana</i>, are in the sectionMacrostigma. Detailed morphological descriptions and illustrations are provided, together with notes on distribution, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. An identification key to the species of sectionMacrostigma is presented. One name, <i>G.thorelii</i>, is lectotypified here. For <i>Garcinianuntasaenii</i> we recommend a conservation status of Endangered [EN B2ab(v)] and for the other two species (<i>G.prainiana</i> and <i>G.thorelii</i>) a conservation status of Least concern [LC]. A number of vegetative characters and features of reproductive organs, especially the flowers, distinguish the two sections and we enumerate these herein.