Description from Flora of China
Unona desmos Dunal var. grandifolia Finet & Gagnepain, Bull. Soc. Bot. France 53(Mém. 4): 81. 1906; Desmos cochinchinensis Loureiro var. grandifolius (Finet & Gagnepain) Jovet-Ast ["Ast"].
Climbers to 5 m tall, woody. Branches subglabrous to hairy when young. Petiole 5-10 mm; leaf blade oblong, 15-28 × 5.5-8 cm, papery to thinly leathery, abaxially sparsely to densely appressed hairy, secondary veins 12-17 on each side of midvein and adaxially flattened, base shallowly cordate to truncate, apex shortly acuminate. Inflorescences fasciculate, (1-)4-flowered. Flowers pendulous. Pedicel 2.5-8 cm, puberulent, glabrescent; bracteoles near pedicel base, ovate, ca. 2.5 mm, abaxially puberulent, adaxially sparsely puberulent. Sepals ovate, 4-10 × 4-7 mm. Outer petals elliptic to lanceolate, 3.5-6 × 1.5-3 cm; inner petals lanceolate, 3-5 × 0.6-1 cm, puberulent on both surfaces. Anthers oblong, ca. 1.5 mm; connectives apically truncate to rounded. Carpels ca. 15; stigmas clavate, apex 2-cleft. Fruiting pedicel 6-8 cm; monocarp stipes ca. 1.6 cm; monocarps ellipsoid or moniliform, 1-5 × ca. 0.6 cm, hairy. Fl. Mar-Apr, fr. May-Sep.
Dense forests or thickets in valleys; 100-500 m. Guangxi, S Yunnan [Vietnam].