Cucurbita L.
Cucurbita L., Sp. Pl. 1010. 1753 (nom. cons.).
Type: Cucurbita pepo L.; Herb. Burser XVII: 103 (UPS), conserved type, designated by C. Jeffrey (1992).
Melopepo Mill., Gard. Dict. Abr. ed. 4. 1754.
Pepo Mill., Gard. Dict. Abr. ed. 4. 1754.
Ozodycus Raf., Atlantic J. 145. 1832.
Sphenantha Schrad., Linnaea 12: 416. 1838.
Mellonia Gasp., Rendiconto Accad. Sci. Soc. Borbon Napoli 6: 411. 1847.

Climbers or trailers with up to 6 m long shoots with hollow stems and fibrous or fleshy roots, annual or perennial herbs with monoecious sex system. The leaves are simple, petiolate, with an ovate-cordate to suborbicular, pedately 3-5(-7)-lobed blade, sometimes with a nasty odour. The tendrils are 2- to 7-fid, rarely simple (absent in cultivars like zucchini). The large flowers stand solitary in axils, some are fragrant. The male flowers have a campanulate or elongated receptacle-tube with five, lanceolate or foliaceous sepals. The corolla is campanulate with five yellow, more or less fused petals. The three stamens are inserted at the base of the tube on short and fleshy filaments. Two anthers are bithecous, one is monothecous, fused into a central head. The reflexed thecae contain pantoporate, echinate, large pollen (124-154 µm in diameter (Khunwasi 1998)). The ovary is oblong, globose, cylindric or pear-shaped, constricted at apex with 3-5 placentae and many horizontal ovules. The short, thick styles are united into a column with usually three, bifid stigmata. The fruit is a large, fleshy, indehiscent pepo of variable form and colour, with woody or corky peduncle, smooth or ribbed, reaching in some cultivars more than 1000 kg, which are the biggest fruits worldwide. The interior tissue is soft, fibrous, white, yellow or orange, sweet or bitter with many, ovate to elliptic, strongly compressed seeds with smooth, cream-coloured or black testa, with or without distinct margin. The chromosome number is n = 20 in C. maxima, C. digitata, C. foetidissima, and C. palmata (McKay 1931, Beevy and Kuriachan 1996).

The 18 species grow in disturbed places, humid ravines, floodplains, tropical deciduous forest, grasslands, deserts, rocky hillsides, oak- and pine-oak forests in tropical and subtropical America; cultivated in tropical, subtropical and temperate regions worldwide.

The genus Cucurbita is placed in tribe Cucurbiteae, where it groups with the Central American genera Peponopsis and Polyclathra (Schaefer et al. 2009; Schaefer & Renner 2011).

Accepted species

Cucurbita andreana Naudin, Rev. Hort. 68: 542. 1896.
Cucurbita argyrosperma C. Huber, Index Seminum 1867: 8. 1867.
Cucurbita cordata S. Watson, Proc. Amer. Acad. Arts 24: 50. 1889.
Cucurbita cylindrata L.H. Bailey, Gentes Herb. 6: 304. 1943.
Cucurbita digitata A. Gray, Pl. Wright. 2: 60. 1853.
Cucurbita ecuadorensis Cutler & Whitaker, Ann. Missouri Bot. Gard. 55: 392. 1969.
Cucurbita ficifolia Bouché, Verh. Vereins Beförd. Gartenbaues Königl. Preuss. Staaten 12: 205. 1837.
Cucurbita foetidissima Kunth, Nov. Gen. Sp. 2: 123. 1817.
Cucurbita fraterna L.H. Bailey, Gentes Herb. 6: 288. 1943.
Cucurbita galeottii Cogn., Monogr. Phan. 3: 551. 1881.
Cucurbita lundelliana L.H. Bailey, Gentes Herb. 6: 297. 1943.
Cucurbita maxima Duchesne, Ess. Hist. Nat. Courges 7. 1786.
Cucurbita moschata Duchesne, Ess. Hist. Nat. Courges 7. 1786.
Cucurbita okeechobeensis (Small) L.H. Bailey, Gentes Herb. 2: 179. 1930.
Cucurbita palmata S. Watson, Proc. Amer. Acad. Arts 11: 137. 1876.
Cucurbita pedatifolia L.H. Bailey, Gentes Herb. 6: 297. 1943.
Cucurbia pepo L., Sp. Pl. ed. 1: 1010. 1753.
Cucurbita radicans Naudin, Ann. Sci. Nat., Bot. V, 6: 8. 1866.

Literature

Beevy, S.S. and P. Kuriachan. 1996. Chromosome numbers of South Indian Cucurbitaceae and a note on the cytological evolution in the family. J. Cytol. Genet. 31: 65-71.

Kates, H.R., Soltis, P.S. and D.E. Soltis. 2017. Evolutionary and domestication history of Cucurbita (pumpkin and squash) species inferred from 44 nuclear loci. Molecular Phylogenetics and Evolution 111: 98-109.

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

McKay, J.W. 1931. Chromosome studies in the Cucurbitaceae. Univ. Calif. Publ. Bot. 16: 339-350.

Sanjur, O.I., Piperno, D.R., Andres, T.C. and L. Wessel-Beaver. 2002. Phylogenetic relationships among domesticated and wild species of Cucurbita (Cucurbitaceae) inferred from a mitochondrial gene: Implications for crop plant evolution and areas of origin. Proc. Natl. Acad. Science 99: 535-540.

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.

Whitaker, T.W. and G. W. Bohn. 1950. The taxonomy, genetics, production and uses of the cultivated species of Cucurbita. Econ. Bot. 4: 52-81.