genus of tropical trees of the chocolate family (Sterculiaceae, order Malvales) that bear fruits enclosing large kola (kola nut), or cola, nuts containing caffeine, tannin, and theobromine. Though native to Africa, two species especially, Cola acuminata and C. nitida, are grown commercially in various tropical regions around the world, the dried kola nuts being used in manufacturing the popular soft drink called cola. The cola drink consists of flavouring extracts of kola nut, spice oils, and other aromatics (and sometimes of coca leaves); carmel colouring; sugar and other sweeteners, singly or in combination; phosphoric acid or citric acid; carbon dioxide for effervescence; and water (86 to 92 percent by volume). In diet cola drinks, artificial flavourings and sweeteners may predominate, and the water content may near 100 percent. In Africa kola nuts are chewed locally as a stimulant. In medicine the refined extract is used as a cardiac and central-nervous-system stimulant.

Mature kola trees may reach 12 to 20 m (40 to 65 feet) in height and grow best in sandy loams at low-lying elevations. These evergreen trees have oblong leathery leaves, yellow flowers, and star-shaped fruit. The podded seeds in the fruit are fleshy, about 2.5 to 4 cm (1 to 1.5 inches) long, and mottled white, brown, or reddish gray and have a bitter taste, though they become aromatic after aging.