Short-lived, often annual, nearly inodorous herb 1-7 dm, glabrous or nearly so; lvs 2-8 cm, bipinnatifid, the ultimate segments mostly elongate, linear or linear-filiform, sometimes shorter and broader; heads several or numerous, the disk 8-15 mm wide; outer invol bracts narrow and scarcely or barely scarious-margined; rays 12-25, 6-13 mm; disk-cors 5-toothed; receptacle hemispheric, rounded; achenes as described in the key; 2n=18, 36. Native of Europe, established along roadsides and in waste places in our range. July-Sept. (M. perforata; M. inodora; Chamomilla i.; C. maritima)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.