Native to Brazil, Bitter Quassia is a small forest tree, typically with a leaning stem, sometimes multiply-stemmed. Leaves are alternate, compound, with 3-5 leaflets, one terminal and the remaining in opposing pairs. The rachis between the leaflets is conspicuously winged. The leaves and bark have an unpleasant bitter flavor if chewed, hence the local name. The species name Amara also means bitter. The flowers are produced in a panicle 15-25 cm long, each flower 2.5-3.5 cm long, bright red on the outside, and white inside. They are tubes with a narrow mouth, somewhat wider at the base. The fruit consists of 4-5 berries held together in a red receptacle; the fruits themselves are green, then turn black when maturing early in the dry season. It is famous and used for the bitterwood or quassia, its heartwood, used as a febrifuge; this contains quassin, a bitter-tasting substance (it is, in fact, the bitterest substance found in nature). Extracts of Q. amara bark containing quassinoids are used as insecticides, being particularly useful against aphids on crop plants. Flowering: October-February.