Exostema
 Exostema is a genus of flowering plants in the family Rubiaceae. It consists of trees and shrubs endemic to the neotropics with most of the species occurring in the West Indies. Estimates of the number of species range from 25 to 44.The type species for the genus is Exostema caribaeum. It is a tree of Central America and the Caribbean. Its lumber is of limited use.Exostema was first named by Christiaan Hendrik Persoon as a subgenus of Cinchona.