Matricaria recutita L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Glabrous branching aromatic annual 2–8 dm; lvs 2–6 cm, bipinnatifid, the ultimate segments linear or filiform; heads ± numerous, the disk 6–10 mm wide; invol bracts all evidently scarious-margined; rays 10–20, 4–10 mm; disk-cors 5-toothed; receptacle conic, acute; achenes as described in the key; 2n=18. Native of Eurasia, now widely intr. along roadsides and in waste places in N. Amer., but less common than no. 1 [Matricaria maritima L.]. (M. chamomilla, misapplied)