Vincetoxicum formosanum (Maxim.) Kuntze

Stems twining, to 3 m, glabrous or sparsely pubescent. Petiole 1-4 cm; leaf blade oblong to elliptic, 2.5-7 × 1.5-5 cm, leathery or thick papery, glabrous, base rounded or cordate, apex acute or rounded-cuspidate, sometimes subacuminate; lateral veins 4-6 pairs. Inflorescences racemelike, often branched, 10-35-flowered, 2.5-3.5 cm; cymules 2-flowered; peduncle 0.5-3 cm, pubescent or glabrous. Pedicel to 5 mm. Sepals ovate-oblong, ca. 5 × 2 mm, ciliate; basal glands 5. Corolla ca. 1 cm in diam., rotate to reflexed, fleshy, glabrous; lobes oblong, 4-5 mm, apex acute. Corona cupular, longer than gynostegium, plicate, margin with 5 long teeth alternating with 5 short-truncate, denticulate lobes. Anther appendages rounded to reniform, mucronate; pollinia broadly ovoid. Stigma head slightly elevated. Follicles lanceolate, 7-9 × 1-1.5 cm, glabrous. Seeds flattened, ovate, ca. 1.5 cm; coma to 4 cm. Fl. May-Oct.

Forests, thickets; low to medium elevations. Taiwan (Taibei and Taizhong, Lanyu and Lutao Islands).

Cynoctonum formosanum Maximowicz, Bull. Acad. Sci. Saint-Petersbourg 23: 370. 1877; Cyathella formosana (Maximowicz) C. Y. Wu & D. Z. Li; C. formosana var. ovalifolia (Tsiang & P. T. Li) C. Y. Wu & D. Z. Li; Cynanchum crassifolium Hatusima (1963), not R. Brown (1810); C. formosanum var. ovalifolium Tsiang & P. T. Li; C. hatusimai P. T. Li; Vincetoxicum formosanum (Maximowicz) Kuntze.