Description from Flora of China
?Helicteres undulata Loureiro; Sterculia balansae Aug. Candolle.
Trees. Branchlets at first pilose. Petiole 2.5-3.5 cm; leaf blade elliptic, lanceolate, or elliptic-lanceolate, 9-20 × 3.5-8 cm, abaxially nearly glabrous, adaxially glabrous, lateral veins 7-9 on each side of midrib, curved upward, connected near margin, base obtuse or nearly rounded, apex acute. Inflorescence paniculate, 4-10 cm, densely many-branched. Calyx reddish, divided almost to base, pubescent abaxially, lobes oblong-lanceolate or oblong-elliptic, 4-6 mm, stellately spreading, margins ciliate, apex obtuse or minutely mucronate. Male flowers: androgynophore 2-3 mm, curved. Anthers ca. 10. Female flowers: ovary globose, hairy. Style curved; stigma minutely 5-lobed. Follicle red when fresh, narrowly ovoid or ellipsoid, 5-7 × 2-2.5 cm, 2-4-seeded, densely puberulent, base attenuate, apex beaked. Seeds black-brown, ellipsoid-ovoid, ca. 1 cm. Fl. Apr-Jun.
This species is the most widely distributed member of the genus in the Flora area. The bark fiber is used for making bags and paper.
Usually near streams. Guangdong, Guangxi, Guizhou, S Sichuan, Yunnan [Laos, Myanmar, Thailand, Vietnam].