Acanthaceae (acanthus family) are found all over the eastern USA, but in the west they are largely restricted to desert areas; south California, Arizona, south New Mexico and Texas. 34 genera and about 125 species occur in the US, again most in the east. Plants are shrubs or herbs, generally quite large. Most flowers have bilateral symmetry. Sepals and petals number four or five, the latter usually fused to form a three-lobed lower lip and a two-lobed upper lip. Flowers contain either two or four stamens. Leaves are usually undivided, opposite, and have entire edges.