Description from Flora of China
Hibiscus simplex Linnaeus, Sp. Pl., ed. 2, 2: 977. 1763; Firmiana platanifolia (Linnaeus f.) Schott & Endlicher; F. simplex var. glabra Hatusima; Sterculia firmiana J. F. Gmelin; S. platanifolia Linnaeus f.; S. pyriformis Bunge; S. simplex (Linnaeus) Druce.
Deciduous trees, up to 16 m tall; bark greenish, smooth. Petiole 15-30 cm; leaf blade cordate, palmately 3-5-lobed, 15-30 cm in diam., lobes triangular, both surfaces glabrous or minutely puberulent, basal veins 7, base cordate, apex acuminate. Inflorescence paniculate, terminal, 20-50 cm. Calyx yellowish green, 7-9 mm, divided nearly to base, lobes linear, twisted outward, abaxially puberulent and yellowish, adaxially villous only basally; pedicel nearly as long as calyx. Male flower: androgynophore as long as calyx, thicker in lower part, glabrous. Anthers 15, irregularly fascicled, pistillode pear-shaped and very small. Female flower: ovary globose, hairy. Follicle membranous, stalked, foliaceous, 6-11 × 1.5-2.5 cm, 2-4-seeded, abaxially puberulent or nearly glabrous. Seeds globose, ca. 7 mm in diam., wrinkled. Fl. Jun. 2n = 40*.
Widely cultivated. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan; cultivated in Europe and North America (United States)].