Dioscorea mexicana

Mexican yam
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
Order:	Dioscoreales
Family:	Dioscoreaceae
Genus:	Dioscorea
Species:	D. mexicana
Binomial name
Dioscorea mexicana
Synonyms[1]
Dioscorea macrostachya Benth. Dioscorea macrophylla M.Martens & Galeotti Dioscorea deppei Schiede ex Schltdl. Dioscorea bilbergiana Kunth Dioscorea leiboldiana Kunth Dioscorea propinqua Hemsl. Testudinaria cocolmeca Procop. Dioscorea astrostigma Uline Dioscorea macrostachya var. sessiliflora Uline Dioscorea tuerckheimii R.Knuth Dioscorea anconensis R.Knuth Dioscorea deamii Matuda Dioscorea mexicana var. sessiliflora (Uline) Matuda Testudinaria macrostachya (Benth.) G.D.Rowley

Dioscorea mexicana, Mexican yam or cabeza de negro is a species of yam in the genus Dioscorea.^[1]

Dioscorea mexicana is a caudiciform dioscorea having either a partly to completely above-ground dome-shaped caudex with a thick, woody outer layer up to 3 feet(90 cm) in diameter and 8-10 inches(20 to 25 cm) in height. The caudex of D. mexicana is divided into regular polygonal plates that become protuberant with age, and separated by deep fissures. The vigorous annual vines which may reach 30 feet (9 m) long before dying back in winter, that grow up from the caudex, bear heart-shaped leaves.^[2]

Dioscorea mexicana ranges from the state of San Luis Potosí in northeastern Mexico south to Panama.^{[3][4][5][6][7][8][9]} It is notable for its production of diosgenin, which is a precursor for the synthesis of hormones such as progesterone.^[10] Russell Marker developed the extraction and manufacture of hormones from D. mexicana at Syntex. Later the Mexican barbasco trade focused instead on Dioscorea composita instead, as this variety has a higher diosgenin content.^[11]

References

1. Kew World Checklist of Selected Plant Families
2. Dortort, Fred(2011). Succulent Plants of the World. Timber Press Inc. pp 220. ISBN 978-0-88192-995-9
3. Téllez V., O. & B. G. Schubert. 1994. 251. Dioscoreaceae. 6: 53–65. In G. Davidse, M. Sousa Sánchez & A.O. Chater (eds.) Flora Mesoamericana. Universidad Nacional Autónoma de México, México, D. F.
4. Sosa, V., B. G. Schubert & A. Gómez Pompa. 1987. Dioscoreaceae. Flora de Veracruz 53: 1–46.
5. Correa A., M.D., C. Galdames & M. Stapf. 2004. Catálogo de las Plantas Vasculares de Panamá 1–599. Smithsonian Tropical Research Institute, Panamá.
6. Pérez J., L. A., M. Sousa Sánchez, A. M. Hanan-Alipi, F. Chiang Cabrera & P. Tenorio L. 2005. Vegetación terrestre. 65–110. In J. Bueno, F Álvarez & S. Santiago Biodiversidad del Estado de Tabasco. CONABIO-UNAM, México.
7. Balick, M. J., M. H. Nee & D.E. Atha. 2000. Checklist of the vascular plants of Belize. Memoirs of The New York Botanical Garden 85: i–ix, 1–246.
8. Nelson Sutherland, C.H. (2008). Catálogo de las plantes vasculares de Honduras. Espermatofitas: 1-1576. SERNA/Guaymuras, Tegucigalpa, Honduras.
9. López Patiño, E.J., Szeszko, D.R., Rascala Pérez, J. & Beltrán Retis, A.S. (2012). The flora of the Tenacingo-Malinalco-Zumpahuacán protected natural area, state of Mexico, Mexico. Harvard Papers in Botany 17: 65-167.
10. ars-grin.gov
11. americanheritage.com

External links