Coffee belongs to the botanical family Rubiaceae, which has some 500 genera and over 6,000 species. Most are tropical trees and shrubs that grow in the lower elevations of forests. Other members of the family include gardenias and plants that yield quinine and other useful substances, but Coffea is by far the most important member of the family.

Below are some of the most important coffea genus species within the Rubiaceae family.

Since Coffea was discovered botanists have failed to agree on a precise classification system. There are probably at least 25 major species, all indigenous to tropical Africa and certain islands in the Indian Ocean, notably Madagascar. Difficulties in classification and even in designation of a plant as a true member of the Coffea genus arise because of the great variation in the plants and seeds. All species of Coffea are woody, but they range from small shrubs to large trees over 30 feet tall; the leaves can be yellowish, dark green, bronze or tinged with purple.

The two most important species of coffee economically are Coffea arabica (Arabica coffee) – which accounts for over 70 percent of world production – and Coffea canephora (Robusta coffee). Two other species which are grown on a much smaller scale are Coffea liberica (Liberica coffee) and Coffea dewevrei (Excelsa coffee).

Once the ripe coffee berries are picked, processed, and dried, they yield contained coffee seeds or ‘beans’. The beans are then roasted to varying degrees, depending on the desired flavor profile. They are then ground and brewed to create coffee.