Coffee Tree Botany

Thanks to Charles at Coffee-a-Go-Go for this information.


Coffee comes from the Latin form of the genus Coffea, a member of the Rubiaceae family which includes more than 500 genera and 6,000 species of tropical trees and shrubs. Eighteenth century Swedish botanist Carolus Linnaeus (1707-1778) first described the genus but, to this day, botanists still disagree on the classification because of the wide variations that occur in coffee plants and seeds. Linnaeus classified the coffee shrubs in the family Rubiacae comprising 4,500 species of which 60 are called 'coffea'. Species of Coffea range from small shrubs to trees as tall as 32 feet high and the leaves can range in colour from purple to yellow, however, green is the predominant colour. After three to four years, when they reach maturity, coffee plants bear fruit in lines or clusters along their branches. The fruit turns red and cherry-like when it is ready to be harvested. Depending on the type of coffee plant, the cherry takes between 6 to 11 months to ripen.

The traditional way to grow coffee trees is to grow compatible trees nearby, to keep the coffee trees and their developing fruit from the sun. The modern techniques are to use irrigation systems and fertilizers. Coffee is grown on both large estates and in the smallest of forest clearings. There are about 25 major species within Coffea, but the typical coffee drinker is likely to be familiar with two: Coffea Arabica and Coffea Canephora (var. robusta).

Coffea Arabica

Arabica represents approximately 70 percent of the world's coffee production. Typica and Bourbon are the two best known varieties of C. Arabica, but many strains have been developed, including Caturra (from Brazil and Columbia), Mundo Novo (Brazil), Tico (Central America), San Ramon and Jamaican Blue Mountain. The Arabica plant is typically a large bush with dark green, oval shaped leaves that can reach a height of 14 to 20 feet fully grown. On plantations, the plants are kept at a height of about three metres to facilitate harvesting. After planting, Arabica trees mature in 3 to 4 years, when they produce their first crop. The Arabica plant can continue to produce fruits for about 50 years although the fruit yield decreases significantly after 30. Arabica trees prefer a seasonal climate of 60-75 degrees Fahrenheit and an annual rainfall of 60 inches. Primary, non-renewable branches grow from the trunk at an average distance of 15 cm, the plants have taproots that are not very deep. The bright green, coriaceous leaves are shiny on top and dull on the underside; they vary from 5 to 20 cm in length and come to a point. Its branches carry bouquets of 5-12 small white flowers with a jasmine-like fragrance that spreads throughout the plantations. The five-petal flowers fade quickly to give rise to the coffee cherry; these are oval-shaped berries with, usually, two beans side-by-side. At high altitudes the plants generally blossom once, while in the lower-lying areas where there are no great seasonal changes the plants blossom several times a year - so that there are almost always fruits on the plants. A hybrid of Arabica, Maragogype - (called the elephant bean because of its large size) - originated from the Maragogype County in the Bahia state of Brazil. Today it is grown in Guatemala, Mexico, Nicaragua, Honduras, El Salvador, Brazil and Zaire.

Coffea Canephora (var. Robusta)

Coffea canephora provides the robusta beans, the most widely grown variety of coffee. Robusta, which can grow up to 32 feet in height as a shrub or tree, has a shallow root system. The fruits are round and take nearly a year to mature. The seeds are rounder and smaller than arabica beans. Robusta coffee is grown in West and Central Africa, throughout Southeast Asia, and parts of South America including Brazil, where it is known as Conilon. Robusta trees produce their first crop 3 to 4 years after planting and they remain fruitful for 20 to 30 years. The trees prefer equatorial conditions with temperatures between 75 and 85 degrees Fahrenheit and an annual rainfall of 60 inches. Before roasting, the color of Robusta beans are yellow to light brown in appearance where Arabica are green with silver/blueish shades.