Cosmocalyx spectabilis is a slender
tree, up to in height and 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. ==Systematics==