Begonia aurantiflora (sect. Coelocentrum, Begoniaceae), a new species from limestone areas in Guangxi, China

Begonia aurantiflora C.-I Peng, Yan Liu & S. M. Ku, a new species of sect. Coelocentrum from Guangxi Zhuangzu Autonomous Region, China, is described and illustrated. Its somatic chromosome number, 2n = 30, is here reported. Begonia aurantiflora is similar to B. debaoensis, differing in the tepals orange; leaves adaxially sparsely long-pilose, fully developed mature leaves often with whitish or silver-white ring-shaped belt on upper surface, peduncle, outer tepals and ovaries moderately pilose or glandular hairy. Begonia aurantiflora is the only species with orange flowers in sect. Coelocentrum. It is also a very rare species with a highly restricted distribution.