Erect, glabrous to hirsute annual or sometimes perennial herb, to c. 80 cm high.
Leaves with lamina triangular-ovate, 3.5–10 cm long, 2.8–9.5 cm wide, cuneate at base, lobed, the middle lobe largest with an acute apex; petiole 2–3.5 cm long.
Flowers solitary, peduncle 2–6 cm long. Calyx lobes ovate, 7–11 mm long, long-acuminate, spreading, pubescent. Petals 8–12 mm long, white, lavender or purplish blue. Schizocarp 10–20 mm diam., seated on enlarged flattened calyx; mericarps 9–20, beaked, bristly or hirsute. Native of Amer.