Cynanchum ovalifolium Wight
Wight, R. (1834) Contrib. Bot. India: 57. Type: India?, Penang, Aug 1827, collector unknown; holo: K - W 8226..
A slender vine not exceeding a stem diameter of 2 cm.
Twigs, petioles and leaves produce a milky exudate. Leaf blades about 7-11 x 4.5-6 cm, petioles about 2.5-4 cm long. A pair of reduced leaves are often present in the axil of one leaf of each pair. These structures resemble leafy stipules and distinguish this species from most others in this genus.
Inflorescence umbelliform, flowering over an extended period of time. Calyx lobes triangular, about 1.5 mm long. Corolla tube about 1 mm long, lobes narrowly triangular, about 7 mm long and usually twisted towards the apex. Stamens fused together to form a structure about 1.8-2.5 x 1.25-1.8 mm. Carpels about 1.5 mm long. Styles free at the base but fused to form a domed style head at the apex.
Fruits inflated, soft and spongy, about 11 x 4.5 cm, green or yellowish when mature. Seeds pyriform, about 12 x 8 mm, plumes white, about 30-35 mm long. Cotyledons about 5 x 4 mm, much wider and longer than the radicle.
Cotyledons elliptic, about 18-21 x 12-16 mm, producing a milky exudate when cut or broken. At the tenth leaf stage: leaf blade elliptic to obovate, glabrous throughout. Petioles grooved on the upper surface. Leaf stem and petiole exudate milky.
Distribution and Ecology