Mayweed, stinking chamomile, camomille maroute

Anthemis foetida Lamarck; Chamaemelum cotula (Linnaeus) Allioni; Maruta cotula (Linnaeus) de Candolle

Annuals, (5–)15–35(–90) cm, usually ill-scented. Stems green (sometimes red-tinged), usually erect, branched mostly distally or ± throughout, glabrous, glabrate, puberulent, or sparsely strigillose to strigoso-sericeous (glabrescent, hairs mostly medifixed) and gland-dotted. Leaf blades 25–55 × 15–30 mm, 1–2-pinnately lobed. Peduncles mostly (2–)4–6(–15) cm. Involucres 5–9 mm diam., ± villosulous to arachnose. Receptacles paleate mostly distally; paleae subulate to acerose 2–3+ mm (often gland-dotted). Ray florets 10–15, styliferous and sterile; corollas white, laminae 5–15+ mm. Disc corollas 2–2.5 mm (sparsely gland-dotted). Cypselae 1.3–2 mm, ribs ± tuberculate (furrows often gland-dotted); pappi 0. 2n = 18.

Flowering (Apr–)May–Aug(–Oct). Disturbed sites, clearings, fields, roadsides; 10–600(–1500+) m; introduced; Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky, La., Maine, Md., Mass., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Eurasia.

Anthemis cotula is a weed throughout North America.