Thladiantha siamensis Craib, Bull. Misc. Inform. Kew 1914: 7. 1914; Momordica tonkinensis Gagnepain.

Plants to 20 m; all parts densely yellow-brown pubescent and red (black when dry) glandular-scaly. Roots enlarged. Petiole 3.5-10 cm; leaf blade ovate-cordate, 10-27 × 2-5.5 cm, membranous, palmately 5-7-veined. Male flowers: 5-15(to many) in a raceme or panicle; peduncle 2-12 cm; pedicels 15-30 mm; calyx tube broadly campanulate, 12-15 mm in diam.; segments ovate-triangular, 3-5 × 7-9 mm, 3-veined, apex obtuse; corolla pale yellow, 3.4-4 cm in diam.; segments ovate-oblong, 15-20 × 9-13 mm, margin with glandular hairs, base with 3 membranous scales, 5-veined, apex obtuse; filaments sparsely glandular hairy. Female flowers solitary or paired; calyx and corolla as in male flowers but smaller; staminodes (3-)5; corolla base with 3 scales; ovary ovoid, 12-15 × 9-10 mm, densely velvety and glandular-scaly, base obtuse-rounded, apex truncate; style 4-5 mm, glabrous, 3-lobed; stigma reniform. Fruit subglobose, ca. 6 cm in diam., velvety at first, glabrescent. Seeds numerous, pale brown, ovoid, 12-14 × 11-13 mm, ca. 4 mm thick, with 3-layered wings; wing corky, margin irregularly dentate, median 3-5 mm wide, lateral 1-2 mm wide. Fl. Apr-Jun, fr. Jul-Sep.

The tuber is used medicinally.

Forests on mountain slopes; 300-700 m. W Guangxi, SE Yunnan [Indonesia, Malaysia, Thailand, N Vietnam].