Perennial climber with succulent, much-branched, five-angled stems, to 3 m high, potato-shaped tubers and dioecious sex system. The leaves are very small, caducuous, 3-5-lobed, the tendrils are simple, partly pubescent, to 20 cm long, caducuous. The flowers are small, male flowers in pedunculate, condensed racemes, female flowers solitary or in pairs. The receptacle-tube is cup- to funnel-shaped with five 2 mm long, triangular sepals. The five petals are elliptic-lanceolate, 1-3 mm long, yellowish-white. The two stamens are inserted near the mouth of the tube on short, pubescent filaments. The anthers are bithecous with straight thecae containing tricolporate, (micro)reticulate, small pollen (polar axis 42-46 µm, equatorial axis 25-31 µm, (Keraudren 1968)). The ovary is ovate-oblong with two placentae, two horizontal ovules per locule and lobed stigmata. The fruit is fleshy, c. 2 cm long, ovoid, apiculate to rostrate, glabrous, indehiscent, ripening brilliant red. The 2-4 seeds are 6-7 mm long, 4 mm large, imbedded in a transparent arilloid and red pulp. The testa is brown, slightly sculptured, without distinct margin. The chromosome number is n = 13 (Keraudren 1968).
Six species endemic to xerothermic forest and bushland in South and Southwest Madagascar. The genus is named after André Seyrig (1897-1945), a French mining engineer and amateur specialist of Ichneumonid wasps.
The genus Seyrigia is place in tribe Coniandreae, where it groups with Trochomeriopsis, from which it split about 15 million years ago (Schaefer et al. 2009).
Seyrigia bosseri Keraudren, Bull. Soc. Bot. France 109: 101. 1962.
Seyrigia gracilis Keraudren, Bull. Soc. Bot. France 107: 299. 1961.
Seyrigia humbertii Keraudren, Bull. Soc. Bot. France 107: 299. 1961.
Seyrigia marnieri Keraudren, Bull. Soc. Bot. France 114: 446-447, f. 1. 1967.
Seyrigia multiflora Keraudren, Bull. Soc. Bot. France 107: 299. 1960.
Seyrigia napifera Rauh, Succ. & Xeroph. Pl. Madagascar 2: 193. 1998.
Keraudren, M. 1968. Recherches sur les cucurbitacées de Madagascar. Mémoires du Muséum National d’Histoire Naturelle. Nouvelle Série. Série B, Botanique 16: 122-330.
Khunwasi, C. 1998. Palynology of the Cucurbitaceae. Doctoral Dissertation Naturwiss. Fak., University of Innsbruck.
Schaefer, H., Heibl, C., and S.S. Renner. 2009. Gourds afloat: a dated phylogeny reveals an Asian origin of the gourd family (Cucurbitaceae) and numerous oversea dispersal events. Proceedings of the Royal Society B 276: 843-851.