Home
Coarse, nearly inodorous, glabrous annual or biennial 3–30 dm; lvs 5–15 cm, pinnatisect nearly to the midrib into several narrow lobes that are usually again sharply toothed, or the lower bipinnatifid; infl dense, spike-like or of spiciform branches, the heads usually numerous, crowded, scarcely pedunculate; invol glabrous, 2–3 mm; achenes ellipsoid, 4–5-nerved; 2n=18. Waste places and stream-banks, especially in sandy soil; native to nw. U.S. but widely distributed in our range and elsewhere as a weed. Aug.–Oct.
A small herb. It grows 30-120 cm high. The leaves are alternate and green. They are smooth on both sides. They are divided into several narrow segments with teeth along the edge. They are 2.5-7.5 cm long. The flowers are in small flower heads. Several occur in dense spikes. The fruit is a small smooth achene.
