This species is variable. It is an annual or perennial herb or subshrub growing 30 centimeters to 2.5 meters tall. The stem is usually thin, about half a centimeter wide, but it can grow thick at the base, up to 2.5 centimeters wide. It is spongy or corky, or sometimes hollow and cylindric. It is mostly hairless but sometimes has glandular hairs with tubercular bases. The leaves are up to 10 centimeters long. Each leaf is made up of many narrow, papery leaflets each up to 1.3 centimeters long. Some leaves are sensitive. The spurred
stipule is up to 1.5 centimeters long. The
inflorescence is made up of 1 to 6 flowers with reddish- or purple-streaked yellow or whitish corollas. The long, narrow
legume pod is up to 4.8 centimeters long and is straight or curved, with up to 13 chambers. It contains black or brown kidney-shaped seeds each 2 or 3 millimeters long. ==Habitat==