Description from Flora of China
Benzoin praecox Siebold & Zuccarini, Abh. Math.-Phys. Cl. Königl. Bayer. Akad. Wiss. 4(3): 205. 1846; Parabenzoin praecox (Siebold & Zuccarini) Nakai.
Deciduous shrubs, up to 4 m tall. Bark black-gray. Young branchlets slender, greenish gray, many lenticellate, rugose; current year branchlets brown, many lenticellate, glabrous. Winter buds corniform-conical, ca. 5 mm. Leaves alternate; petiole 0.5-1 cm, glabrous; leaf blade greenish abaxially, dark green adaxially, ovate or elliptic, 5-9 cm × 2.5-4 mm, glabrous, pinninerved, lateral veins 4 pairs, convex abaxially, slightly concave adaxially, base broadly cuneate, apex acuminate. Umbels each inserted at both sides of leaf bud; peduncles glabrous, 4-4.5 mm; involucral bracts 4, red, exserted parts glabrous, 5-flowered inside. Male flowers: tepals broadly elliptic, ca. 2 × 1.5 mm in outer whorl, ca. 1.7 × 1.3 mm in inner whorl, glabrous or laxly white pubescent on outer surface, densely pubescent on inner surface; stamens equal in length, glabrous, 2-glandular at filament base in 3rd whorl; glands broadly reniform, long stipitate, various in shape and size; reduced pistil long corniform-conical. Female flowers: pedicels densely white pubescent; tepals broadly elliptic, ca. 1.5 × 1 mm in outer whorl, ca. 1.2 mm and less than 1 mm wide in inner whorl, laxly white pubescent on outer surface, rather densely pubescent on inner surface; reduced stamens fasciated, 2-glandular at filament base in 3rd whorl; glands reniform, long stipitate; ovary ellipsoid, ca. 1 mm, glabrous; style ca. 1/2 as long as ovary; stigma small, disciform, red-brown. Fruits globose, up to 1.5 cm in diam., yellow-brown at maturity; stipes 7-10 mm, lenticellate, gradually thickened toward apex; hypocarpium nearly 3 mm in diam. Fl. Mar, fr. Sep.
Thickets on hills or mountain slopes. Anhui, Hubei, Zhejiang [Japan].