Rubiaceae () is a family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with interpetiolar stipules and sympetalous actinomorphic flowers. The family contains about 14,200 species in about 615 genera, which makes it the fourth-largest angiosperm family by number of species. Rubiaceae has a cosmopolitan distribution; however, the largest species diversity is concentrated in the tropics and subtropics. Economically important genera include Coffea, the source of coffee; Cinchona, the source of the antimalarial alkaloid quinine; ornamental cultivars (e.g., Gardenia, Ixora, Pentas); and historically some dye plants (e.g., Rubia).
Description
The Rubiaceae are morphologically easily recognizable as a coherent group by a combination of characters: opposite or whorled leaves that are simple and entire, interpetiolar stipules, tubular sympetalous actinomorphic corollas and an inferior ovary.
A wide variety of growth forms are present: shrubs are most common (e.g. Coffea, Psychotria), but members of the family can also be trees (e.g. Cinchona, Nauclea), lianas (e.g. Psychotria samoritourei), or herbs (e.g. Galium, Spermacoce). Some epiphytes are also present (e.g. Myrmecodia). The plants usually contain iridoids, various alkaloids, and raphide crystals are common. The leaves are simple, undivided, and entire; there is only one case of pinnately compound leaves (Pentagonia osapinnata). Leaf blades are usually elliptical, with a cuneate base and an acute tip. In three genera (Pavetta, Psychotria, Sericanthe), bacterial leaf nodules can be observed as dark spots or lines on the leaves. The phyllotaxis is usually decussate, rarely whorled (e.g. Fadogia), or rarely seemingly alternate resulting from the reduction of one leaf at each node (e.g. Sabicea sthenula). Characteristic for the Rubiaceae is the presence of stipules that are mostly fused...
