Ampelosicyos A. Thouars
Ampelosicyos A. Thouars, Hist. Vég. Isles Austr. Afrique 68. 1808. [as Ampelosycios]
Type: Ampelosicyos scandens L.M.A. du Petit-Thouars s.n. (P), Foulpointe, Mahavelona, Madagascar.
Delognaea Cogn., Bull. Mens. Soc. Linn. Paris 425-427. 1884.
Tricyclandra Keraudren, Bull. Soc. Bot. France 112: 327. 1966.
Odosicyos Keraudren, Bull. Soc. Bot. France, Lett. Bot. 127: 518. 1981.
Mostly monoecious (A. meridionalis Keraudren perhaps dioecious), perennial, herbaceous to woody climbers or trailers growing several meters long up into the trees. Some (or all) have partly exposed, tuberous rootstocks reaching up to 1m or more in diameter. The leaves are simple, petiolate, pedately 3-5-lobed or 3-5-foliolate with oblong-lanceolate, entire or deeply lobed leaflets. The tendrils are simple or 2-fid, long, glabrous or (partly) pubescent. The flowers are medium-sized to large, open at night and emit a light, pleasant fragrance, which attracts sphingid moths. The male flowers are produced in small racemes or solitary, female flowers always solitary. The receptacle-tube is elongate, cylindrical, apically expanded, up to 20 cm long and 2 mm across near the base, apically expanded up to 12 mm. The 5 sepals are triangular-dentiform and 1-2 mm long. The 5 petals are free or ± fused, up to 3 cm long, ± ellipsoidal, white to yellowish in colour, their margin with up to 2 cm long fringes. The 3 or 5 stamens are inserted near the mouth of the tube, the thecae of the monothecous anthers are triplicate or circular. The pollen is medium-sized (polar and equatorial axis c. 46-66 µm), tri(col)porate, (micro)reticulate, verrucate or striato-reticulate (Keraudren 1968). The ovary is smooth with 3 placentae and many, horizontal ovules. The 3 stigmas are bilobed. The fruit is a ± pear-shaped or ellipsoid, fleshy to fibrous pepo, 7-15 cm long, smooth, indehiscent, yellow with whitish pulp. It contains 5-25 obovate, bean-shaped, up to 3 cm long and 2 cm wide seeds, which are rich in oil. Their testa is pale cream-coloured or brown, smooth, without a distinct margin.
The five species of this genus are all endemic to Madagascar, where they are found in rainforest forest remnants but also in dry bushland and deciduous forest. All five are highly endangered due to habitat loss and seem to be restricted to National Parks. Ampelosicyos bosseri seems to suffer also from illegal collecting for the succulent ornamental market.
Ampelosicyos bosseri (Keraudren) H. Schaef. & S.S.Renner, Taxon 60: 133. 2011.
Ampelosicyos humblotii Jum. & H.Perrier, Ann. Fac. Sc. Marseille 23: 29. 1915.
Ampelosicyos leandrii (Keraudren) H.Schaef. & S.S.Renner, Taxon 60: 133. 2011.
Ampelosicyos meridionalis Keraudren, Bull. Soc. Bot. France 112: 71. 1965.
Ampelosicyos scandens Thouars, Hist. Veg. Isles Afr. austr. 68, t. 22. 1807.
Keraudren, M. 1968. Recherches sur les cucurbitacées de Madagascar. Mem. Mus. Hist. Nat. B. 16(2): 122-330.
Keraudren-Aymonin, M. 1971. La survivance des Ampelosicyos (Cucurbitacees) a Madagascar. Bull. Soc. Bot. France 118: 281-286.
Rauh, W. 1998. Succulent and xerophytic plants of Madagascar. Vol. 2. Strawberry Press, Mill Valley.