Echinopepon.

Echinopepon Naudin
Echinopepon Naudin, Ann. Sci. Nat. Bot. ser. 5. 6: 17. 1866.
Type: Echinopepon horridus Naudin, Bourgeau s.n. (P), Mexico, lectotype designated by Stocking, Madroño 13: 87. 1955.
Brandegea Cogn., Proc. Calif. Acad. Sci. ser. 2. 3: 58. 1890.
Vaseyanthus Cogn., Zoë 1: 368. 1891.
Apatzingania Dieterle, Brittonia 26: 131. 1974.

Annual or perennial climbers with up to 5 m long herbaceous shoots, fibrous roots or woody rootstock, and monoecius sex system. The leaves are simple, petiolate, with thin, angulate-cordate, often palmately 3-5(-9)-lobed or dissected blades, the margin entire or denticulate. The tendrils are simple or 2-3-fid. The flowers are small, the male inflorescence is a raceme or panicle, the female flowers are mostly solitary. The receptacle-tube is cup-shaped to urceolate or shallowly campanulate with five small or minute, green sepals. The corolla is rotate or campanulate with five ovate-triangular, white or cream-coloured petals, sometimes knobby-glandular (E. insularis). The filaments of the three to five stamens are fused into a central column, the anthers are all free, bithecous. The thecae are straight, curved or duplicate. The pollen is 5-14-colpate or colporate, some pantocolpate-inaperturate, sometimes the colpi with distinct margines, perforate (some weakly verrucate or micro-reticulate) medium-sized to large (polar axis 58-168 µm, equatorial axis 78-168 µm, (Khunwasi 1998)). The ovary is conic to ovoid, ± rostrate, with one or two placentae and 1-5 erect to ascending (rarely horizontal or pendent) ovules per locule. The style is short with fleshy, subglobose stigma. The fruit is ovoid or ellipsoid, operculate, glabrous or hairy, often conspicuously echinate, rostrate. In E. arachoidea the fruit is dry, subterranean (to 3.5 cm deep), on 6-9 cm long peduncle. The seeds are solitary or few, quadrangular or angular-ovoid, compressed with smooth, rugose or sculptured testa. The chromosome number is n = 12 (Ward and Spellenberg 1988).

The 22 species grow in forest-clearings, semi-deserts and ravines, on hillsides, roadsides, sand dunes and seaside gravel shores from the Southern United States to Northern Argentina. Some are weeds of cultivated ground.

Phylogenetically, Echinopepon is sister to a clade comprising Cyclanthera and Hanburia, from which it split about 15 million years ago (Schaefer et al., 2009; Schaefer & Renner 2011).

Accepted species

Echinopepon arachoideus (Dieterle) A.K. Monro & Stafford, Ann. Missouri Bot. Gard. 85: 268. 1998.
Echinopepon belizensis A.K. Monro & Stafford, Ann. Missouri Bot. Gard. 85: 269. 1998.
Echinopepon bigelovii (S. Watson) S. Watson, Proc. Amer. Acad. Arts 24: 52. 1889.
Echinopepon calcitrapa McVaugh, Fl. Novo-Galiciana 3: 561. 2001.
Echinopepon cirrhopedunculatus Rose, Contr. U. S. Natl. Herb. 1: 106. 1891.
Echinopepon coulteri (A. Gray) Rose, Contr. U. S. Natl. Herb. 5: 116. 1897.
Echinopepon disjunctus Pozner, Syst. Bot. 29: 605. 2004.
Echinopepon glutinosus (Cogn.) A.K. Monro & Stafford, Ann. Missouri Bot. Gard. 85: 268. 1998.
Echinopepon insularis S. Watson, Proc. Amer. Acad. Arts 24: 51. 1889.
Echinopepon jaliscanus Rose, Contr. U. S. Natl. Herb. 5: 117. 1897.
Echinopepon longispinus (Cogn.) Rose, Contr. U. S. Natl. Herb. 5: 117. 1897.
Echinopepon micropaniculatus A.K. Monro & Stafford, Ann. Missouri Bot. Gard. 85: 269. 1998.
Echinopepon milliflorus Naudin, Ann. Sci. Nat., Bot. V, 6: 18. 1866.
Echinopepon minimus (Keller) S. Watson, Proc. Amer. Acad. Arts 24: 52. 1889.
Echinopepon palmeri S. Watson, Proc. Amer. Acad. Arts 24: 52. 1889.
Echinopepon pringlei Rose, Contr. U. S. Natl. Herb. 5: 117. 1897.
Echinopepon pubescens (Cogn.) Rose, Contr. U. S. Natl. Herb. 5: 118. 1897.
Echinopepon racemosus (Steud.) C. Jeffrey, Kew Bull. 33: 357. 1978.
Echinopepon rosei (Cogn.) H. Schaef. & S.S. Renner, Taxon 60: 134. 2011.
Echinopepon torquatus (Cogn.) Rose, Contr. U. S. Natl. Herb. 5: 118. 1897.
Echinopepon tultitlanapaensis A.K. Monro & Stafford, Ann. Missouri Bot. Gard. 85: 265. 1998.
Echinopepon wrightii (A. Gray) S. Watson, Bull. Torrey Bot. Club 14: 158. 1887.

Literature

Dieterle, J. V. A. 1974. A new geocarpic genus from Mexico: Apatzingania (Cucurbitaceae). Brittonia 26: 129-132.

Gentry, A. 1950. Taxonomy and evolution of Vaseyanthus. Madroño 10: 142-155.

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

Monro, A. K. and P. J. Stafford. 1998. A synopsis of the genus Echinopepon (Cucurbitaceae: Sicyeae), including three new taxa. Ann. Missouri Bot. Gard. 85: 257-272. 1998.

Rose, J. N. 1897. Echinopepon and its allies. Contr. U.S. Natl Herb. 5: 114-121.

Pozner, R. 2004. A new species of Echinopepon from Argentina and taxonomic notes on the subtribe Cyclantherinae (Cucurbitaceae). Syst. Bot. 29: 599-608.

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.

Stocking, K. M. 1955. Some considerations of the genera Echinocystis and Echinopepon in the United States and northern Mexico. Madroño 13: 84-100.

Ward, D.E., Spellenberg, R. 1988. Chromosome counts of angiosperms from New Mexico and adjacent areas. Phytologia 64: 390-398.