Saturday, August 3, 2019

Erythroxylum: The Coca Plant :: Botany

Erythroxylum: The Coca Plant The coca plant is a member of the order Geraniales and the family Erythroxylaceae. There are four genera with an estimated 200 species in Erythroxylaceae (De Witt, 1967). Coca was first described as Erythroxylum by A.L. Jussieu in 1783. It was given the binomial Erythroxylum coca by Lamarck in 1786. Early botanists believed that all coca plants were of the same species. Later researchers found that two species of domesticated coca existed. These are Erythroxylum coca Lam. and Erythroxylum novogranatense (Morris) Hieron (Rury and Plowman, 1983). The two species have two varieties, Erythroxylum coca Lam. var. coca, E. coca var. Ipuda Plowman, E. novogranatense (Morris) Hieron var. novogranatense, and E. novogranatense var. truxillense (Rusby) Plowman (Plowman, 1983). Distribution Coca is grown in South America, Africa, Ceylon, Taiwan, Indonesia and Formosa (De Witt, 1967). Coca is most commonly associated with its center of origin, the South American Montana zone of the eastern Andes below 2000m (Bray & Dollery, 198:3). According to Rury and Plowman (1983) E. coca var. Coca, Huanuco or Bolivian coca is the ancestral variety. Bolivian coca grows in the moist tropical forests of the eastern Andes of Peru and Bolivia. This variety is the only one of the four found growing wild. Bolivian coca is the major source of commercially produced coca leaves and cocaine. Amazon coca, E. coca var. ipuda is cultivated in the lowland Amazon. It has been suggested that this variety is a lowland cultigen of Bolivian coca. In contrast to Bolivian coca it is not found growing wild (Rury and Plowman, 1993). E. novogranatense var. truxillense or Trujillo coca is a hardy, drought resistant variety. It is found growing in river valleys of coastal Peru and other arid areas of this region. Bohm, Ganders & Plowman (1982) state that this variety displays many characteristics that are intermediate between E. coca var. coca and E. novogranatense var. novogranatense, and may represent an evolutionary stage between these species. E. novogranatense var. novogranatense or Colombian coca is cultivated in both moist and dry areas in the Colombian mountains. It is also drought tolerant and is not found growing outside Cultivation. Evidence shows that this variety maybe the most evolved species (Rury & Plowman, 1983). Cultivation Coca plants are small evergreen shrubs with reddish brown bark. They have many small branchlets with elliptical-obovate opposite leaves measuring 4-7 cm. in length and 3-4 cm.

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