Bidens comosa, Wiegand Native. Annual. Propagates by seeds.
Time of bloom: August to October.
Seed-time: September to November.
Stem one to three feet high, stout, erect, smooth, pale green, with short, stout branches. Leaves light green, lance-shaped, regularly toothed, pointed at both ends, with winged petioles or the upper ones sessile. Heads large, on short, stout peduncles, the outer bracts of the involucre six to eight, lance-shaped, large, and leaflike, often toothed, erect, their height sometimes two to five times exceeding the disk; rays wanting; disk-florets funnel-shaped, four-lobed, pale yellow. Achenes brown or olive, nearly a half-inch in length, flat, smooth or nearly so, three-awned, the outer ones nearly three-fourths as long as the achene, the central one usually shorter, and all barbed downward.
Control of the weed depends on allowing none of the plants to mature their fruits.