With leaflets opposite or alternate (spaced), sometimes with scattered thickenings or depressions.

They generally have a vestigial ovary in the male flowers which is sunk in the disk, of 5 carpels with very short connate styles and 5 stigmas.

The fruit (or seed capsule) consists of 1–3 disruptive mericarps.

Plants of the World Online lists 2 accepted species;[2] It is an accepted genus by GRIN (United States Department of Agriculture and the Agricultural Research Service), but they only list 1 species, Hannoa undulata (Guill.

[3] While World Flora Online lists it as a synonym of Quassia L.[4] As listed by Plants of the World;[2] They are native to Cameroon, Nigeria, Sudan and Zaïre.