Description from Flora of China
Megalotropis Griffith; Meizotropis Voigt; Plaso Adanson.
Trees, climbing to erect shrubs, or perennial herbs. Leaves pinnately 3-foliolate; stipules small to medium-sized, caducous. Flowers large, orange-red or red, densely clustered in axillary or terminal racemes or panicles; bracts and bracteoles small, caducous. Calyx campanulate; teeth short, obtusely triangular, upper 2 connate into a broad entire or emarginate lip. Corolla medium-sized to large, exserted; petals subequal in size; standard ovate or lanceolate, apex acute, recurved, not appendaged; wings falcate, adherent to keel; keel longest, incurved, apex acute, back connate into a ridge. Stamens diadelphous; anthers uniform. Ovary sessile or shortly stipitate, 2-ovuled; style elongated, incurved, glabrous; stigma small, terminal. Legumes oblong, compressed, apex rounded, with 1 seed at top, empty and not dehiscent in lower part, often with stipe at base. Seed obovate; hilum small, estrophiolate.
Meizotropis, with two species, was recognized by Sanjappa (Bull. Bot. Surv. India 29: 199-225. 1989), as well as by Schrire (in Lewis et al., Legumes World, 408. 2005). A broader view of Butea is taken here, but the matter is in need of further study.
Four or five species: Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Laos, Myanmar, Nepal, Sri Lanka, Thailand, Vietnam; three species (one endemic) in China.
(Authors: Chen Dezhao (陈德昭 Chen Te-chao), Zhang Dianxiang (张奠湘); Mats Thulin)