Raphidiocystis Hook.f.
Raphidiocystis Hook.f. in Benth. & Hook., Gen. 1: 828. 1867.
Type: Raphidiocystis mannii Hook.f., G. Mann 363 (K, P), Equatorial Guinea, Fernando Póo [Bioko], 1860.

Perennial climber with up to 6 m long herbaceous shoots and monoecious sex system. The leaves are simple, with ovate-cordate blade and entire or sinuate margin, petiolate, with elliptic, hooded probract at the base of the petiole. The tendrils are simple. Flowers are produced in racemes, often male and female flowers coaxillary. The receptacle-tube is short, obconic or cylindrical with five triangular-lanceolate sepals, in some species the sepals are pinnately divided and convoluted, up to 10 mm long and broad. The corolla is campanulate to urceolate with five entire, reflexed petals, yellow to orange in color. The three stamens are inserted in the lower half of the tube on long filaments. The anthers are all bithecous with triplicate thecae, which contain tricolporate, reticulate, medium-sized pollen (polar axis 56-73 µm, equatorial axis 44-70 µm, (Khunwasi 1998, Keraudren 1968)). The ovary is ellipsoid, densely bristly, with many, horizontal ovules. The style is columnar with three lobed stigmata. The fruit is fleshy, ellipsoid to spherical, up to 7 cm long, densely brown-setose, ripening reddish, dehiscing into ten longitudinal valves and extruding the seeds in red pulp at the apex (Zimmermann 1922). The many seeds are smooth, broadly ovate, c. 5 mm long and 4 mm broad, compressed.

The five species grow in clearings or along rivers of lowland rainforest, four throughout tropical Africa and one is endemic to Madagascar (R. brachypoda).

Raphidiocystis is placed in the tribe Benincaseae (Schaefer et al. 2019), where it groups with Cephalopentandra, Lemurosicyos, Borneosicyos, and Solena (Schaefer & Renner 2011) but its exact position so far has not been resolved.

Literature

Keraudren, M. and C. Jeffrey. 1967. Le genre Raphidiocystis (Cucurbitaceae) en Afrique et à Madagascar. Bull. Jard. Bot. Nat. Belg. 37: 319-328.

Keraudren, M. 1968. Recherches sur les cucurbitacées de Madagascar. Mém. Mus. Hist. Nat. B 16: 122-330.

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.

Zimmermann, A. 1922. Die Cucurbitaceen. Beiträge zur Anatomie, Physiologie, Morphologie, Biologie, Pathologie und Systematik. Vols. 1 and 2. Jena: Fischer.