Three new species of Begonia (sect. Petermannia, Begoniaceae ) from Sarawak, Borneo

Borneo is a hotspot for Begonia. About 140 species of Begonia have been described from Borneo, 75 of which occur in Sarawak. In this study we report the discovery of three undescribed species of Begonia, namely B. amidalae, B. darthvaderiana and B. anserina from southwestern Sarawak. They are assignable to sect. Petermannia based on the cane-like habit, protogynous inflorescence and pistillate flowers with three locules each with two placentas. The new species B. amidalae somewhat resembles B. subisensis K.G. Pearce, but is sharply distinct by the leaf shape, tepal color, much fewer stamens and smaller pistillate tepals and fruits. Begonia darthvaderiana is similar to B. chlorosticta Sands differing in the leaf shape, orientation and maculation, much fewer stamens, color of staminate tepals as well as shape of fruit wings. Begonia anserina approaches B. pleioclada Irmsch. in the sympodial branching, differing in being a much taller plant with shorter inflorescence and larger fruits.