Anthemis arvensis
Sp. Pl. 2: 894. 1753.
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.
Phenology: Flowering May–Jul(–Sep).
Habitat: Disturbed sites, abandoned plantings
Elevation: 10–400+ m
Distribution
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.
Discussion
Anthemis arvensis is morphologically variable; it is found throughout much of North America.
Selected References
None.