This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Annual. Propagates by seed.
Time of bloom: August to October.
Seed-time: September to November.
Range: Illinois to Nebraska, and southward to Louisiana, Texas, and New Mexico. Habitat: Meadows and fields, sides of streams, and waste places.
A coarse, unsightly weed, bristly with rough hairs, two to seven feet in height, the erect stem usually simple but sometimes branched and often mottled with different shades of green. Leaves opposite, broadly ovate, pointed, three-nerved, coarsely and irregularly toothed, narrowed abruptly to bristly petioles. Heads in dense terminal and axillary spikes, subtended by narrowly lance-shaped, spreading, very hairy bracts, much longer than the greenish heads, which are scarcely an eighth of an inch in diameter. Involucre hairy, its bracts three to five, distinct or sometimes united at base; central florets staminate; fertile florets, marginal, three to five. Achenes about an eighth of an inch long, without pappus, similar to those of Poverty Weed but ribbed on the face. They are to be guarded against in alfalfa seed from the Southwest. (Fig. 314.)
Prevent seed production. Meadows infested with this weed should be harvested early, before the plants have matured. Its bristly and woody stems are rejected by cattle as fodder, and if the plants are not extremely numerous it would pay to remove them by hand-pulling from a good stand of alfalfa. Plants along ditches and streams should be destroyed by hoe-cutting or mowing while young.
 
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