, the only US species of this genus, is found in desert regions of south Arizona, and also in Florida. Plants are shrubs, several feet tall, branching freely and bearing numerous, closely-spaced leaves. Branches have a sparse hair covering when young. Leaves are stalkless, undivided, linear in shape and crossed by a prominent, lighter-colored midvein. Much fainter side veins branch off, most visible on the undersurface.
Flowers are small - about 0.2 inches across - colored pale yellow, and produced in clusters; they have four or five short sepals surrounding a center of eight to ten stamens or one pistil. The fruit is a capsule with three or four chambers, colored greenish yellow, light orange or light purple. Plants can bloom any time of the year, most strongly in spring, summer and early fall.