Persea is a genus of about 150 species of evergreen trees belonging to the laurel family, Lauraceae. The best-known member of the genus is the avocado, P. americana, widely cultivated in subtropical regions for its large, edible fruit.
They are medium-size trees, 15-30 m tall at maturity. The leaves are simple, lanceolate to broad lanceolate, varying with species from 5-30 cm long and 2-12 cm broad, and arranged spirally or alternately on the stems. The flowers are in short panicles, with six small greenish-yellow perianth segments 3-6 mm long, nine stamens and an ovary with a single embryo. The fruit is an oval or pear-shaped drupe, with a fleshy outer covering surrounding the single seed; size is very variable between the species, from 1-1.5 cm in e.g. P. borbonia and P. indica, up to 10-20 cm in P. americana.
Philip Miller derived Persea from the Greek name Περσεα. It was applied by Theophrastus and Hippocrates to an uncertain Egyptian tree, possibly Cordia myxa or a Mimusops species.
Distribution and ecology
The species of Persea have a disjunct distribution, with about 70 Neotropic species, ranging from Brazil and Chile in South America to Central America and Mexico, the Caribbean, and the southeastern United States; a single species, P. indica, endemic to the Macaronesian islands, including Madeira and the Canary Islands; and 80 species inhabiting east and southeast Asia. None of the species is very tolerant of severe winter cold, with the hardiest, P. borbonia, P. ichangensis and P. lingue, surviving temperatures down to about -12°C; they also require continuously moist soil, and do not tolerate drought. A number of these species are found in forests that face threats of destruction or deforestation; for example, P. meyeniana occurs in Central Chile, where historic and ongoing deforestation has reduced the habitat of the endangered Chilean Wine Palm and forest system as a whole.
Fossil evidence indicates that the genus originated in West Africa during the Paleocene, and spread to Asia, to South America, and to Europe and thence to North America. It is thought that the gradual drying of Africa, west Asia, and the Mediterranean from the Oligocene to the Pleistocene, and the glaciation of Europe during the Pleistocene, caused the extinction of the genus across these regions, resulting in the present distribution.
Persea species are used as food plants by the larvae of some Lepidoptera species including Giant Leopard Moth, Coleophora octagonella (feeds exclusively on P. carolinensis) and Hypercompe indecisa.
The genus Persea is treated in three subgenera. The Asian subgenus Machilus is treated in a separate genus Machilus by many authors, including in the Flora of China, while graft-incompatibility between subgenus Persea and subgenus Eriodaphne suggests that these too may be better treated as distinct genera, in fact Kostermans (1993) founded the genus Mutisiopersea for these. Another closely related genus, Beilschmiedia, is also sometimes included in Persea.
Subgenus Persea - Central America. Two species.
* Persea americana Mill. – Avocado
Subgenus Eriodaphne (Mutisiopersea) - The Americas, Macaronesia. About 70 species, including
* Persea alpigena
Subgenus Machilus - Asia. About 80 species, including
* Persea edulis
* Cinnamodendron cinnamomifolium (Kunth) Kosterm. (as P. cinnamomifolia Kunth or P. mexicana (Meisn.) Hemsl.)
1. ^ a b "Genus: Persea Mill.". Germplasm Resources Information Network. United States Department of Agriculture. 2007-10-05. http://www.ars-grin.gov/cgi-bin/npgs/html/genus.pl?9138. Retrieved 2011-02-05.
* André Joseph Guillaume Henri Kostermans. 1993. Mutisiopersea Kostermans, a new genus in Lauraceae. Rheedea 3: 132–135.
Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License