1. Anthemis arvensis Linnaeus, Sp. Pl. 2: 894. 1753.
Corn chamomile, fausse camomille, anthémis des champs
Anthemis arvensis var. agrestis (Wallroth) de Candolle; Chamaemelum arvense (Linnaeus) Hoffmannsegg & Link
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.