This native annual grows from 1 to 3 feet tall. The alternate, pinnately compound leaves are divided into 8-15 opposite pairs of narrow, delicate leaflets less than 1 inch long (A). Leaflets are sensitive, folding along the midrib when touched. Showy flowers with 5 unequal bright yellow petals alternating with pointed green sepals arise at the junction of the leaf and stem. The upper 4 petals have a dark reddish spot at the base but the larger, lower petal does not (B). The petals surround 10 unequal stamens, the larger ones dark reddish with drooping anthers and the others yellow and inconspicuous (B). The fruit is an erect flat brown pod up to 2 1/2 inches long (C).