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 seeds.
Time of bloom: Early August to October.
Seed-time: September to November.
Range: Virginia to Kansas, southward to Florida and Texas.
Habitat: Prairies; moist meadows, roadsides, and waste places.
This plant is rapidly extending its range, being locally established as far north as Massachusetts and Ohio; it is considered quite as noxious as the larger, perennial species, several cases having been reported from the Gulf States where it has proved fatal to grazing horses and mules. Neat cattle do not seem to be so dangerously affected, but the weed is often the cause of bitter milk. The bitter, acrid properties are not dissipated by drying and therefore the young plants are very objectionable in meadows, being harvested with the hay and sharply "cutting" its quality.
Stem eight to twenty inches tall, slender, smooth, much branched above, forming a bushy head. Leaves very numerous, smooth, linear, almost thread-like, sessile, often fascicled. Heads many, about an inch broad, with six to ten short, drooping, yellow rays, fanshaped, toothed at the tips, pistillate and fertile; disk yellow, globose, the florets perfect and fertile; bracts of the involucre linear, soon reflexed. Achenes angled and hairy, with a pappus of short, bristle-tipped scales.
Fig. 335. - Purple-headed Sneezeweed (Helenium nudiflorum.) X 1/4.
Prevent seed production by close cutting or hand-pulling when the plant is in first bloom.