A revision and one new species of Begonia L. (Begoniaceae, Cucurbitales) in Northeast India

Following a taxonomic revision of Begonia L. (Begoniaceae, Cucurbitales) from Northeast India based on 332 herbarium specimens, 38 species are confirmed to occur in the region, of which ten are endemic. One new species is described, Begonia koelzii R.Camfield sp. nov., in B. sect. Platycentrum (Klotzsch) A.DC. One species is reduced into synonymy; B. barbata Wall. is now a synonym of B. thomsonii A.DC. Three species, B. difformis (Irmsch.) W.C.Leong, C.I Peng & K.F.Chung, B. labordei H.Lév. and B. handelii Irmsch., are reported new for India, and B. lushaiensis C.E.C.Fisch. is reinstated as an accepted species, having previously been synonymised under B. modestiflora Kurz. A key to the species in the region and preliminary conservation assessments are presented.