The wood of several tropical American trees of the order Simarubeæ, as Quassia amara, Picræna excelsa, and Simaruba amara. It is intensely bitter, and is used in medicine and sometimes as a substitute for hops in making beer.
handsome South American shrub or small tree having bright scarlet flowers and yielding a valuable fine-grained yellowish wood; yields the bitter drug quassia from its wood and bark
Quassia is a genus in the family Simaroubaceae. Its size is disputed; some botanists treat it as consisting of only one species, Quassia amara from tropical South America, while others treat it in a wide circumscription as a pantropical genus containing up to 40 species of trees and shrubs.