Bidens vulgata Greene
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Much like no. 9 [Bidens frondosa L.], averaging a little more robust and larger- headed, the herbage glabrous to densely villous-puberulent; outer invol bracts in well developed heads 10–16(–21), typically 13, averaging a little more leafy; disk yellow; anthers mostly included; achenes to 12 mm, dark as in no. 9, or more commonly olivaceous or somewhat yellowish; 2n=24, 48. Wet to dryish waste places; widespread in n. U.S. and adj. Can., s. to N.C., Mo., and Calif. Aug.–Oct. (B. puberula)