Illinois sensitive (Desmanthus illinoensis) is a hardy perennial herb growing from 1 to 3 feet tall, having soft fern-like foliage. The leaflets contract close to the stem at night. The somewhat woody, erect, smooth stems are strongly angled and branch from the base of the plant. The greenish-white, fuzzy, ball-like flowers form a spherical cluster atop a short stem arising from the base of the leaves. These plants bloom in mid-summer. The woody fruit (seed pods) are crescent shaped, borne in clusters, containing 2 to 5 seeds each and are easily recognized.