The Annonaceae are a family of flowering plants consisting of trees, shrubs, or rarely lianas commonly known as the custard apple family or soursop family. With 108 accepted genera and about 2400 known species, it is the largest family in the Magnoliales. Several genera produce edible fruit, most notably Annona, Anonidium, Asimina, Rollinia, and Uvaria. Its type genus is Annona. The family is concentrated in the tropics, with few species found in temperate regions. About 900 species are Neotropical, 450 are Afrotropical, and the remaining are Indomalayan. Asimina triloba, the American papaw, pawpaw, paw paw, or paw-paw, among many regional names, is a small deciduous tree native to the eastern United States and Canada, producing a large, yellowish-green to brown fruit. It belongs to the genus Asimina in the same plant family (the Annonaceae) as the custard-apple, cherimoya, sweetsop, ylang-ylang, and soursop. The pawpaw is a patch-forming (clonal) understory tree found in well-drained, deep, fertile bottomland and hilly upland habitat, with large, simple leaves. Pawpaw fruits are the largest edible fruit indigenous to the United States (not counting gourds, which are typically considered vegetables rather than fruit for culinary purposes, although in botany they are classified as fruit).