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Coffea is a genus of flowering plants in the Rubiaceae family. They are shrubs or small trees native to tropical and southern Africa and tropical Asia. Seeds of several species are the source of the popular beverage coffee. Coffee ranks as one of the world's most valuable and widely traded commodity crops and is an important export product of several countries. The leaves and the outer part of the fruit are also sometimes eaten.[1]
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There are several species of Coffea that may be grown for the beans. The trees produce red or purple fruits called "cherries" that are drupes. The cherries contain two seeds, the so-called "coffee beans", which — despite their name — are not true beans. In about 5-10% of any crop of coffee cherries, there is only a single bean, rather than the two usually found. This is called a peaberry, which is smaller and rounder than a normal coffee bean. It is often removed from the yield and either sold separately, (as in New Guinea peaberry) or discarded.
When grown in the tropics, coffee is a vigorous bush or small tree that usually grows to a height of 3–3.5 m (10–12 feet). Most commonly cultivated coffee species grow best at high elevations but are nevertheless intolerant of subfreezing temperatures.
The tree of Coffea arabica will grow fruits after three to five years, and will produce for about 50 to 60 years (although up to 100 years is possible). The white flowers are highly scented. The fruit takes about nine months to ripen.
The caffeine in coffee "beans" is a natural plant defense against herbivory, i.e. a toxic substance that protects the seeds of the plant.
Several insect pests affect coffee production, including the coffee borer beetle (Hypothenemus hampei) and the coffee leafminer (Leucoptera caffeina).
Coffee is used as a food plant by the larvae of some Lepidoptera (butterfly and moth) species, including napoleon jacutin (Dalcera abrasa), turnip moth and some members of the genus Endoclita, including E. damor and E. malabaricus.
In 2008 and 2009, researchers from the Royal Botanic Gardens, Kew named seven species of Coffea from the mountains of northern Madagascar, including C. ambongensis, C. boinensis, C. labatii, C. pterocarpa, C. bissetiae, and C. namorokensis.[2]
In 2008, two new species of coffee plants have been discovered in Cameroon: Coffea charrieriana, which is caffeine-free, and Coffea anthonyi.[3] By crossing the new species with other known coffees, two new features might be introduced to cultivated coffee plants: beans without caffeine and self-pollination.
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