Conyza bonariensis (L.) Cronquist
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Annual, 1–10+ dm, copiously and loosely hairy, habitally like no. 1 [Conyza canadensis (L.) Cronquist], or often with some of the lateral branches elongate and overtopping the central axis; lower lvs in robust plants sometimes to 15 × 2 cm; heads larger than in no. 1, the disk often over 1 cm wide; invol 4–6 mm, copiously short-hairy; pistillate fls (50–)70–200+, with a very short or scarcely developed ray to 0.5 mm, this generally surpassed by the style and equaling to more often surpassed by the often tawny or reddish pappus; 2n=54. A weed in waste places, widespread in trop. Amer. and occasionally intr. in se. U.S., n. to Va. Summer. (C. floribunda; Erigeron b.; Leptilon b.)