＂Begonia natunaensis＂ (sect. ＂Reichenheimia,＂ Begoniaceae), a new species from Natuna Island, Indonesia

Abstract

＂Begonia natunaensis＂, a new species of sect. ＂Reichenheimia＂ from Natuna Island, Indonesia, is here described and illustrated. ＂Begonia natunaensis＂ resembles ＂B. goegoensis＂ N.E. Brown in having suborbicular, peltate leaves with an abruptly tapering tip, differing in the number of tepals in staminate flowers (2vs.4) and in pistillate flower (2vs.3) and the petiole (terete vs. 4-angular). The new species is also similar to another peltate-leaved ＂Begonia＂, ＂B. sudjanae＂ Jans., but is distinguishable by being glabrous (vs. hispid throughout), the staminate tepals 2 [vs. (2-)4], and pistillate tepals 2 [vs. (2-)3]. Geographically, ＂B. natunaensis＂ is endemic to Natuna Island in the South China Sea, whereas ＂B. goegoensis＂ and ＂B. sudjanae＂ are distributed in western Sumatra, ＂ca＂. 1,000 km away from Natuna.