This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Bidens vulgata, Greene Native. Annual. Propagates by seeds.
Time of bloom: August to October.
Seed-time: September to November.
Range: Ontario to British Columbia, southward throughout the United States, but not common in the eastern part. Habitat: Moist soil; fields, waste places.
Much taller than the preceding plant, sometimes attaining eight feet or more, smooth, and much branched. Leaves pinnately three-to five-parted, with slender petioles and long-pointed, coarsely toothed leaflets. Heads large, often an inch or more broad, on stout peduncles; involucre of ten to sixteen outer bracts, usually longer than the disk, bristle-edged, unequal; the inner row short, with abruptly narrowed tips; rays when present, pale yellow, small, neutral; disk-florets funnel-form, four- to five-toothed, also pale yellow. Achenes oblong wedge-shaped, brown or olive, very flat, the faces usually smooth but sometimes roughened with fine tubercles, the awns and the upper part of the achenes downwardly barbed.
Means of control the same as for the preceding species.
 
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