Begonia wui-senioris (sect. Platycentrum, Begoniaceae), a new species from Myanmar

The flora of Myanmar is under-collected compared with all other tropical Asian countries. An unknown Begonia was grown from seeds collected from a limestone hill in Central Myanmar, and compared with potentially allied species. The unknown Begonia is rhizomatous, has peltate leaves, 2-locular ovaries, and is evergreen. It is clearly assignable to sect. Platycentrum. Only two other species of Begonia, B. josephii and B. subperfoliata, in Myanmar have peltate leaves, but they are deciduous tuberous plants with 3-locular ovaries and belong to sect. Diploclinium. Thorough studies of literature and herbarium materials support the recognition of a new species, Begonia wui-senioris, which is fully described and illustrated. Begonia wui-senioris has the lowest chromosome number (2n = 14) for the genus.