Description from Flora of China
Erythrina monosperma Lamarck, Encycl. 2: 391. 1786; Butea frondosa Roxburgh ex Willdenow, nom. illeg. superfl.
Trees, 10-20 m tall. Trunk to 30 cm d.b.h. Bark grayish black. Petiole ca. 10 cm, robust; stipels subulate, ca. 1.5 mm; petiolules robust, ca. 8 mm; leaflets unequal, thickly leathery, rough on both surfaces, puberulent along veins abaxially, glabrous adaxially, lateral veins 6 or 7 pairs, like midrib raised abaxially, reticulate veins distinct and with conspicuous areoles abaxially; terminal leaflet broadly obovate or suborbicular, 14-17 × 12-15 cm, base broadly cuneate, apex rounded or emarginate; lateral leaflets narrowly ovate or oblong, 11.5-16 × 8.5-10 cm, asymmetric, base rounded, apex obtuse or emarginate. Racemes or panicles axillary or at nodes of leafless branches; rachis, pedicels, and calyx outside densely brown or blackish brown velutinous. Calyx 1-1.2 cm, densely silvery gray on both surfaces or light brown pubescent inside. Corolla orange-red, becoming yellow later, ca. 3 × as long as calyx; standard narrowly ovate, recurved, 4-4.5 cm; wings narrowly falcate, ca. 4 cm, like keel with rounded auricles at base; keel broadly falcate, 5-5.5 cm, connate into an arcuate ridge, densely silvery gray velutinous. Anthers oblong. Ovary densely velutinous. Legumes 12-15 × 3.5-4 cm, adpressed silvery gray puberulent, apex rounded; stipe 12-15 mm. Seed reddish brown, broadly reniform or reniform-orbicular, compressed, ca. 2.7 × 3.3-3.6 cm. Fl. Mar-Apr.
This species is one of the main host plants of lac insects. The red resin from the bark is used medicinally as an astringent.
Forests, wet places, near roads, also cultivated. SW Guangxi (Ningming), S and SW Yunnan (Gengma, Xishuangbanna) [Bhutan, Cambodia, India, Indonesia, Laos, Myanmar, Nepal, Sri Lanka, Thailand, Vietnam].