Cosmocalyx is a monotypic genus of flowering plants in the family Rubiaceae. The genus contains only one species, viz. Cosmocalyx spectabilis, which is found in Mexico, Belize, and Guatemala.[1]
Cosmocalyx spectabilis is a slender tree, up to 15m (49feet) in height and 20cm (10inches) in diameter (dbh). After anthesis, one of the four calyx lobes expands into a reddish, leaf-like structure called a calycophyll. These facilitate dispersal of the fruit by wind. The fruit is a cylindrical indehiscent bilocular capsule. Each locule contains one basally inserted seed. This combination of characters distinguishes Cosmocalyx from other genera in Rubiaceae.[2]
Cosmocalyx was named by Paul Standley in 1930.[3] The generic name is derived from the Ancient Greek words, kosmos, meaning "order", and kalyx, "a calyx".[4]
Cosmocalyx is placed with Deppea, Hoffmannia, Hamelia and several other genera in the tribe Hamelieae. Relationships within this tribe are uncertain.[5]