Ixoroideae
Ixoroideae is a subfamily of flowering plants in the family Rubiaceae and contains about 4000 species in 27 tribes. Classification. Ixoroideae is a subfamily of the family Rubiaceae. Based on both morphological and molecular characters, Rubiaceae has been divided into three subfamilies - Ixoroideae, Cinchonoideae, and Rubioideae. Ixoroideae and Cinchoinoideae are more closely related. Members of Ixoroideae are morphologically diverse so no shared derived characters have been established for its classification. Introduction of molecular analyses to systematics dramatically improved tribal classification within the subfamily. Present tribal classification within this subfamily is mainly supported through molecular analysis of chloroplast DNA. Cultivation  and use. Ixoroideae consists of 27 tribes that include several economically valuable genera. Well-known genera within the subfamily include "Ixora" and "Gardenia", both popular ornamentals, but economic value is centered on the genus "Coffea", cultivated for coffee production. Three species are generally used for cultivation - "Coffea arabica", "Coffea robusta", and "Coffea liberica"