It is native to the southwestern United States and northwestern Mexico, where it grows in many types of coastal and inland habitat, from mountains to desert.

This is an annual herb producing a slender, rough-haired stem, generally upright to erect in form to a maximum height of 25 centimeters.

The small, pointed linear leaves are alternately arranged, widely spaced along the stem.

The flower has small green sepals and a tiny white corolla.

The fruit is an array of four flattened, slightly curving nutlets lined with thin teeth.