Annuals (sometimes persisting), (5-)10-30+[-80] cm, not notably scented. Stems green or reddish, decumbent (sometimes rooting at nodes) or ascending to erect, branched mostly proximally, ± strigoso-sericeous or villous, glabrescent. Leaf blades 15-35 × 8-16 mm, 1-2-pinnately lobed (ultimate lobes triangular to narrowly elliptic or linear). Peduncles mostly 4-15 cm (sometimes clavate in fruit). Involucres 6-13 mm diam., ± villous. Receptacles paleate throughout; paleae lanceolate to oblanceolate, weakly navicular (± carinate), 3-4+ mm (including acuminate-spinose tips). Ray florets 5-20, pistillate, fertile; corollas white, rarely tinged with pink, laminae 5-15 mm. Disc corollas (sometimes tinged with purple) 2-3(-4) mm. Cypselae 1.7-2+ mm, ribs smooth or weakly tuberculate (sometimes separated by relatively deep furrows); pappi 0 or coroniform (0.01+ mm). 2n = 18. Flowering May-Jul(-Sep). Disturbed sites, abandoned plantings; 10-400+ m; introduced; B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que.; Ala., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Ky., La., Maine, Md., Mass., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., R.I., S.C., Tenn., Vt., Va., Wash., W.Va., Wyo.; Europe. Anthemis arvensis is morphologically variable; it is found throughout much of North America.
Similar to no. 3 [Anthemis cotula L.], commonly a little more hairy, and not ill-scented; lvs appearing a little less finely dissected; heads averaging a little larger; rays pistillate and fertile; receptacle chaffy throughout, its bracts softer, paleaceous, with short, cuspidate awn-tip; achenes not tuberculate; 2n=18. Fields and waste places; native of Europe, naturalized over most of the U.S., and widespread in our range. May-Aug.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.