Sicyos L.
Sicyos L., Sp. Pl. 2: 1013. 1753.
Type: Sicyos angulatus L., Herb. Clifford 452, Sicyos no. 1 (BM, Lectotype).
Sicyoides Mill., Gard. Dict. Abr. ed. 4. 1754.
Sechium P. Browne, Civ. Nat. Hist Jamaica 355.1756 (nom. cons.).
Bryoniastrum Heist. ex Fabr., Enum. 195. 1759.
Chayota Jacq., Select. Stirp. Amer. Hist. (ed. 1780 -1781) 124, t. 245. 1780.
Sicyosperma A. Gray, Smithsonian Contr. Knowl. 5: 62-63. 1853.
Sechiopsis Naudin, Ann. Sci. Nat., Bot., ser. 5, 6: 23-24. 1866.
Microsechium Naudin, Ann. Sci. Nat., Bot., ser. 5, 6: 25. 1866.
Pterosicyos Brandegee, Univ. Calif. Publ. Bot. 6: 72. 1914.
Ahzolia Standl. & Steyerm., Publ. Field Mus. Nat. Hist., Bot. Ser. 23: 92. 1944.
Anomalosicyos Gentry, Bull. Torrey Bot. Club 73: 565. 1946.
Sicyocaulis Wiggins, Madroño 20: 251. 1970.
Skottsbergiliana H. St. John, Pacific Sci. 28: 457. 1974.
Parasicyos Dieterle, Phytologia 32: 289. 1975.
Sicyocarya (A. Gray) H. St. John, Phytologia 38: 407. 1978.
Sarx H. St. John, Bot. Jahrb. Syst. 99: 491. 1978.
Cladocarpa (H. St. John) H. St. John, Bot. Jahrb. Syst. 99: 491. 1978.
Costarica L. D. Gómez, Phytologia 53: 97. 1983.
Annual or perennial climbers or trailers with up to 10 m long herbaceous shoots, fibrous to tuberous roots and monoecious sex system. The leaves are simple, petiolate (rarely sessile), with angulate or lobed blade. The tendrils are simple or (2-) 3-5 (-6)-fid, often with long stout peduncle. The flowers are small, white or yellowish-green. Male flowers are produced in racemes or panicles (rarely umbels), the female flowers solitary or in groups of 2-5 or in dense capitulae of up to 40. The receptacle-tube is (broadly) campanulate, in some species with pouch-like nectaries at the base. The five sepals ar dentiform to linear, very small. The corolla is rotate with five triangular to ovate-triangular, basally fused, rarely bifurcate petals. The 2-5 stamens are inserted near the base of the tube on filaments, which are fused into a central column. The anthers are all monothecous or two anthers bithecous and one monothecous, all anthers usually form a central head. The thecae are straight, duplicate, sigmoid or flexuous and contain 6-12-colpate, echinate, small to medium-sized pollen (polar axis 31-92 µm, equatorial axis 34-110 µm, (Khunwasi 1998)). The ovary is ovoid to fusiform, usually pubescent to setose, rarely winged or angular with solitary, pendent ovules. The styles are short or slender with (2-) 3 dilated, often reflexed stigmata. The fruits are dry or fleshy, indehiscent, solitary or clustered in capitulae, sometimes enclosed by a subtending leaf, small or medium-sized, globose, ovoid, obovoid, pear-shaped, fusiform, pedicellate, winged or 3-4 angled, armed with retrorse barbs or unarmed, glabrous or villous. The solitary seed is ovoid, tumid or compressed, sometimes germinating inside the fruit. The testa is smooth or crustaceous. The known chromosome numbers range from n = 12-15.
About 60-70 species growing on forest margins, hillsides, clearings, roadsides, pastures, and in seabird colonies, most from Mexico to Argentina, Hawaii, North America, Australia, New Zealand, Southwest Pacific (Islas Desventuradas), Galapagos (S. pentagonus, S. villosus) one species, S. polyacanthus in Africa (introduced). The chayote or xuxu, Sicyos edulis, is cultivated as a vegetable throughout the Tropics and Subtropics.
The genus Sicyos is placed in tribe Sicyeae (Schaefer et al. 2009, Schaefer & Renner 2011).
Accepted species
Sicyos acarieanthus Harms, Repert. Spec. Nov. Regni Veg. 19: 172. 1923.
Sicyos albus (H. St. John) I. Telford, Phytologia 67: 210. 1989.
Sicyos ampelophyllus Wooton & Standl., Bull. Torrey Bot. Club 36: 111. 1909.
Sicyos andreanus Cogn., Bull. Acad. Roy. Belgique, sér. 2, 49: 200. 1880.
Sicyos angulatus L., Sp. Pl. 1013. 1753.
Sicyos anunu (H. St. John) I. Telford, Phytologia 67: 211. 1989.
Sicyos australis Endl., Prodr. Fl. Norfolk. 67. 1833.
Sicyos baderoa Hook. & Arn., Bot. Misc. 3: 324. 1833.
Sicyos barbatus (Gentry) C. Jeffrey, Kew Bull. 33: 362. 1978.
Sicyos bogotensis Cogn., Monogr. Phan. 3: 874. 1881.
Sicyos bulbosus Rodríguez-Arévalo, Lira & Dávila, Bot. J. Linn. Soc. 145: 373-375. 2004.
Sicyos chaetocephalus Harms, Repert. Spec. Nov. Regni Veg. 19: 172. 1923.
Sicyos chiriquensis Hammel & D’Arcy, Ann. Missouri Bot. Gard. 68: 215-217. 1981.
Sicyos collinus Robinson & Fern., Proc. Amer. Acad. Arts 30: 116 1894.
Sicyos cordifolius Rodríguez-Arévalo, Lira & Dávila, Bot. J. Linn. Soc. 145: 375-378. 2004.
Sicyos cucumerinus A. Gray, U.S. Expl. Exped., Phan. 1: 652. 1854.
Sicyos davilae Rodríguez-Arévalo & Lira, Bol. Soc. Bot. México 68: 81-84. 2001.
Sicyos debilis Cogn. ex Kuntze, Revis. Gen. Pl. 3: 104. 1898.
Sicyos dieterleae Rodriguez-Arevalo & Lira, Acta Bot. Mex. 48: 15. 1999.
Sicyos edulis Jacq., Enum. Syst. Pl. 32. 1760.
Sicyos galeottii Cogn., Monogr. Phan. 3: 883. 1881.
Sicyos glaber Wooton, Bull. Torrey Bot. Club 25: 310. 1898.
Sicyos gracillimus Cogn., Monogr. Phan. 3: 886. 1881.
Sicyos guatemalensis Standl. & Steyerm., Publ. Field Mus. Nat. Hist., Bot. Ser. 23: 96. 1944.
Sicyos herbstii (H. St. John) I. Telford, Phytologia 67: 210. 1989.
Sicyos hillebrandii H. St. John, Occas. Pap. Bernice Pauahi Bishop Mus. 10: 7. 1934.
Sicyos hispidus Hillebr., Fl. Hawaiian Isl. 136. 1888.
Sicyos ignarus Mart. Crov., Bonplandia (Corrientes) 1: 359. 1964.
Sicyos kunthii Cogn., Monogr. Phan. 3: 888-889. 1881.
Sicyos laciniatus L., Sp. Pl. 2: 1013. 1753.
Sicyos laevis A. Gray, U.S. Expl. Exped., Phan. 1: 648. 1854.
Sicyos lanceoloideus (H. St. John) W.L. Wagner & D.R. Herbst, Novon 9: 444. 1999.
Sicyos lirae Rodríguez-Arévalo, Brittonia 55: 69-72. 2003.
Sicyos longisepalus Cogn., Bot. Gaz. 16: 11. 1891.
Sicyos longisetosus Cogn., Monogr. Phan. 3: 882. 1881.
Sicyos macrocarpus Cogn., Monogr. Phan. 3: 893. 1881.
Sicyos macrophyllus A. Gray, Proc. Amer. Acad. Arts 3: 54. 1853.
Sicyos malvifolius Griseb., Abh. Königl. Ges. Wiss. Göttingen 19: 147. 1874.
Sicyos martii Cogn., Fl. Bras. 6: 109. 1881.
Sicyos maximowiczii Cogn., Monogr. Phan. 3: 895. 1881.
Sicyos mcvaughii Rodríguez-Arévalo, Lira & Calzada, Ismael, Brittonia 57: 43-46. 2005.
Sicyos microphyllus Kunth, Nov. Gen. Sp. (4th ed.) 2: 119. 1817.
Sicyos montanus Poepp. & Endl., Nov. Gen. Sp. Pl. 2: 53–54, t. 172. 1838.
Sicyos odonellii Mart. Crov., Lilloa 27: 305. 1955.
Sicyos pachycarpus Hook. & Arn., Bot. Beechey Voy. 83. 1832.
Sicyos parviflorus Willd., Sp. Pl. 4: 626. 1805.
Sicyos peninsularis Brandegee, Zoë 5: 159. 1903.
Sicyos polyacanthos Cogn., Fl. Bras. 6(4): 107. 1878.
Sicyos sertulifer Cogn., Bull. Soc. Roy. Bot. Belgique 30: 277. 1891.
Sicyos triqueter Ser., Prodr. 3: 309. 1828.
Sicyos urolobus Harms, Notizbl. Bot. Gart. Berlin-Dahlem 11: 775. 1933.
Sicyos vargasii Standl. & F.A. Barkley, Bull. Torrey Bot. Club 74: 82. 1947.
Sicyos villosus Hook.f., Trans. Linn. Soc. London 20: 223. 1847.
Sicyos weberbaueri Harms, Repert. Spec. Nov. Regni Veg. 19: 173. 1923.
The following species belong in Sicyos but so far do not have a valid name in that genus:
Microsechium gonzalo-palomae Lira, Anales Inst. Biol. Univ. Nac. Autón. México, Biol. 65: 74-80. 1994.
Microsechium palmatum (Ser.) Cogn., Monogr. Phan. 3: 911-912. 1881.
Parasicyos dieterleae Lira & R. Torres, Acta Bot. Mex. 16: 98-99. 1991.
Parasicyos maculatus Dieterle, Phytologia 32: 289-290. 1975.
Sechium chinantlense Lira & F. Chiang, Novon 2: 229. 1992.
Sechium compositum (Donn. Sm.) C. Jeffrey, Kew Bull. 33: 361. 1978.
Sechium hintonii (Paul G. Wilson) C. Jeffrey, Kew Bull. 33: 360. 1978.
Sechium mexicanum Lira & M. Nee, Brittonia 51: 204-209. 1999.
Sicyosperma gracile A. Gray, Smithsonian Contr. Knowl. 5: 62-63. 1853.
Sechiopsis diptera Kearns, Syst. Bot. 17: 400-402. 1992.
Sechiopsis distincta Kearns, Syst. Bot. 17: 405-407. 1992.
Sechiopsis laciniata (Brandegee) Kearns, Syst. Bot. 17: 402-403. 1992.
Sechiopsis tetraptera Dieterle, Contr. Univ. Michigan Herb. 14: 69-71. 1980.
Sicyocaulis pentagonus Wiggins, Madroño 20: 252. 1970.
Literature
Carr, G. D. 1985. Additional chromosome numbers of Hawaiian flowering plants. Pacific Science. 39: 302-330.
Kearns, D. M., 1992. A revision of Sechiopsis (Cucurbitaceae). Syst. Bot. 17: 395-408.
Khunwasi, C. 1998. Palynology of the Cucurbitaceae. Doctoral Dissertation Naturwiss. Fak., University of Innsbruck.
Lira, R. and F. Chiang. 1992. Two new combinations in Sechium (Cucurbitaceae) from Central America and a new species from Oaxaca, Mexico. Novon 2: 227-231.
Mercado, P. and R. Lira. 1994. Contribution al conocimiento de los numeros chromosomicos de los generos Sechium P. Br. y Sicana Naudin (Cucurbitaceae). Acta Botanica Mexicana 27: 7-13.
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.