Schizocarpum Schrad.
Schizocarpum Schrad., Index Sem. Gött. 1830: 4. 1830.
Type: Schizocarpum filiforme Schrad., H. Schrader 9 (LE), cultivated in Spangenberg (Germany) from seed collected in Mexico, 1822.

Annual or perennial climbers with up to 7 m long, herbaceous shoots and monoecious sex system. The leaves are simple, petiolate, with entire to 3-5-lobed blade, the tendrils are bifid. The flowers are solitary, large, showy. The receptacle-tube is elongated, subcylindric at base, expanded distally with five reflexed or ascending, linear, ovate or triangular sepals. The corolla is campanulate, yellow with dark central spot inside, the five petals are fused in the lower half, triangular. The three stamens (rarely two or four), are inserted near the mouth of the tube on free filaments. The anthers are connate into a central ovoid head with triplicate thecae containing pantoporate, echinate, large pollen (polar axis 119-125 µm, equatorial axis 119-125 µm, (Khunwasi 1998)). The ovary is ovoid to fusiform, often rostrate with three placentae and 12 or more, ascending ovules. The style is slender with three fleshy stigmas 3. The fruit is a dry, woody capsule, ellipsoid to pear-shaped, smooth, rostrate, indehiscent or dehiscing into three lobes from the apex downwards, each with two rows of seed chambers, followed by the abscission of the pericarp. The seeds are ovoid, compressed, 8-10 mm long with smooth testa, brown or banded crosswise with light and dark stripes, margin with or without wing.

Ten species in oak or pine forest, tropical deciduous forest, disturbed ground, coastal plains in Mexico and Guatemala.

Schizocarpum is placed in tribe Cucurbiteae but its exact position is still unclear (Schaefer et al. 2009, Schaefer & Renner 2011).

Literature

Jeffrey, C. 1971. Further notes on Cucurbitaceae: 2. The tribe Cucurbiteae. Kew Bulletin 25:191-236.

Khunwasi, C. 1998. Palynology of the Cucurbitaceae. Doctoral Dissertation Naturwiss. Fak., University of Innsbruck.

Schaefer, H. and S.S. Renner. 2011. Phylogenetic relationships in the order Cucurbitales and a new classification of the gourd family (Cucurbitaceae). Taxon 60: 122-138.

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.