Description from Flora of China
Benzoin supracostatum (Lecomte) Rehder; Lindera supracostata var. attenuata C. K. Allen.
Evergreen shrubs or trees, (1.5-)3-15(-25) m tall, ca. 20 cm d.b.h. Bark brown, with longitudinally split striae, gray-brown. Terminal bud broadly ovate; bud scales gray-white sericeous-pubescent outside. Leaves alternate; petiole ca. 1 cm, glabrous; leaf blade pale abaxially, green and shiny adaxially, elliptic, ovate, or lanceolate, 5-10 × 2.3-4 cm, glabrous on both surfaces, trinerved or triplinerved, veins more convex adaxially than abaxially, base cuneate or broadly cuneate, margin ± repand, apex caudate-acuminate. Umbels 1 or 2, inserted at upper part of branch in leaf axil, subsessile, male umbel 5-flowered, female umbel 3-8-flowered. Male flowers yellow-green; tepals 6, oblong, ca. 3.5 mm, pubescent outside; stamens 9, ca. 2.5 × 1 mm; filament pubescent, 2-glandular near base of filament in 3rd whorl; glands globose, shortly stipitate; reduced pistil ca. 2.5 mm; ovary ovate, ca. 1 mm; style equal to length of ovary, pubescent. Female flowers yellow-green; tepals 6, oblong, ca. 2 mm; filament 2-glandular at middle in 3rd whorl; glands oblong-globose, shortly stipitate; ovary ellipsoid, ca. 2 × 1.2 mm, pubescent; style ca. 1.5 mm, pubescent; stigma disciform. Fruits ovate, 8-9 mm, black-purple at maturity; stipes 7-11 mm, gradually thickened into a disciform 3-5 mm in diam. hypocarpium. Fl. Mar-May, fr. Jul-Sep.
The width and basal shape of the leaf blade are variable in different plants, as well as on the same plant, so separate varieties based on those characters are not recognized here.
● Valleys or dense forests on mountain slopes; 2400-2800 m. W Guizhou, W Sichuan, C and NW Yunnan.