Begonia fulgurata (sect. Diploclinium, Begoniaceae), a new species from northern Thailand

Begonia fulgurata, a new species from northern Thailand, is here described and illustrated. Begonia fulgurata resembles B. integrifolia, a widespread species in Southeast Asia, in having tubers, erect stem with hairy leaves and a periodically dormant habit. However, the new species is sharply distinct in its lamina densely hirsute (vs sparsely puberulous) and with maroon patches and silvery white veins (vs uniformly green or with white spots); inflorescence densely clothed with glandular hairs (vs glabrous or puberulous); staminate flowers with 2, rarely 3 (vs 4) tepals; staminate and pistillate tepals glandular hairy (vs glabrous). As a deciduous species with basal tubers, together with an erect stem, ovate to broadly ovate leaves, 3-locular ovary, it may be mistaken as a dwarf plant of B. grandis, one of the most widely distributed species in China and the type species of sect. Diploclinium. However, B. fulgurata differs in its leaf upper side with fine silvery (vs green) veins; inflorescence densely glandular hairy (vs glabrous), staminate tepals 2 or rarely 3 (vs 4) and pistillate tepals 5 (vs 3), and ovary glandular hairy (vs glabrous).