Clonostylis is a monotypic genus of flowering plant in the family Euphorbiaceae. The sole species is Clonostylis forbesii is a flowering tree found in Sumatra. It has small glabrous leaves with an elliptic shape, arranged spirally.
It was previously thought that Clonostylis S.Moore was a synonym of Spathiostemon Blume, but now Clonostylis is provisionally treated as a monotypic genus.
Since only one specimen has been found, according to the Nationaal Herbarium Nederland, and it did not exhibit fruit or staminate flowers, a more definite classification is not yet possible. (The species is unisexual, and the specimen in question had only pistillate flowers.)[1]