Merremia tuberosa (PROSEA)
Merremia tuberosa (L.) Rendle
- Protologue: Fl. Trop. Afr. 4(2): 104 (1905).
Ipomoea tuberosa L. (1753), Operculina tuberosa (L.) Meissn. (1869).
- Wood rose, Brazilian jalap (En)
- Indonesia: areuy kawoyang (Sundanese)
- Vietnam: bìm củ.
Probably of Central American origin, now distributed throughout tropical Africa, the Mascarene Islands, India and Sri Lanka; in India and Malesia cultivated as a medicinal and sometimes escaped from cultivation.
In South-East Asia, the tuber is used as a drastic purgative. The plant is also planted as an ornamental in Africa. The woody fruits are used in flower arrangements in Europe.
A perennial, glabrous twiner, 3-5 m long, stems robust, finely striate, tuber large; leaves orbicular in outline, 6-16 cm × 6-16 cm, palmately divided to far below the middle, segments 7, oblong-lanceolate, apex acuminate, base narrowed, entire, the middle segment larger than the lateral ones, petiole 6-18 cm long; flowers in a few-flowered cyme, peduncle 4-15 cm long, bracts triangular, small; flower-buds oblong, apex pointed, pedicel 15-18 mm long, in fruit clavate, up to 5 cm long, sepals subequal, outer ones 25 mm long, ovate, obtuse, inner ones oblong, in fruit 5-6 cm long, enclosing the capsule, corolla funnel-shaped, 5.5 cm long, yellow, anthers twisted; capsule subglobose, 3.5 cm in diameter, pericarp thin, splitting irregularly, and loosening circumsessile at base; seeds 17 mm long, black, black pubescence on sides. In Indonesia, M. tuberosa occurs from sea-level up to 600 m altitude. The loosening of the capsulewall is different from that of Operculina , where the wall shows 2 layers, and the outer one is fleshy in the upper part, forming an operculum.