Rubiaceae

Large family of plants, having over 10,000 species in about 630 genera distributed worldwide, especially in tropical and subtropical regions. Most members of the family are trees and shrubs, though a few are annual plants. Examples include species of economic importance such as coffee (Coffea) and quinine (Cinchona), and also species such as Gardenia, cultivated for its fragrant flowers.

The leaves are generally in opposite pairs and each has at its base a pair of outgrowths or stipules, which may be fused, branched, or otherwise modified in various ways. In the British species, the stipules resemble leaves, so that the leaves appear to be in whorls of four to eight around the stem, but each group of apparent leaves has only two axillary buds. The flowers are generally borne in groups. They have four or five sepals, petals, and stamens, the petals usually forming a tube to which the stamens are attached. The ovary consists of two fused carpels, and is situated below the other floral parts. The fruit is dry in the British species, but tropical Rubiaceae often have berries.