122. Anthemis Linnaeus, Sp. Pl. 2: 893. 1753; Gen. Pl. ed. 5, 381. 1754.
Chamomile [Greek anthemon, flower]
Linda E. Watson
Annuals (biennials) [perennials, subshrubs], mostly 5–90 cm (often aromatic). Stems 1–5+, erect to decumbent, usually branched, strigillose or strigoso-sericeous to villous (hairs medifixed), glabrescent [glabrous or sericeous to lanate]. Leaves mostly cauline; alternate; petiolate or sessile; blades ± obovate to spatulate, 1–3-pinnately lobed, ultimate margins dentate to lobed, faces glabrous or strigillose to villous [glabrous or sericeous to lanate]. Heads radiate [discoid], borne singly or in lax, corymbiform arrays (peduncles sometimes clavate and/or curved in fruit). Involucres obconic to hemispheric or broader, 5–13[–20] mm diam. Phyllaries persistent, mostly 21–35+ in 3–5 series, distinct, deltate to lanceolate, oblong, or elliptic, unequal, margins and apices (hyaline and colorless or brownish [black]) scarious. Receptacles hemispheric to narrowly conic, paleate (wholly or only distally); paleae ± flat, scarious to indurate (subulate or elliptic to obovate with mucronate to acuminate-spinose tips). Ray florets [0 or 2–]5–20[–30+], pistillate and fertile or styliferous and sterile; corollas usually white, rarely yellow or pink, laminae mostly oblong (tubes sometimes hairy). Disc florets (60–)100–300+, bisexual, fertile; corollas usually yellow, rarely pink, tubes ± cylindric (usually proximally dilated, ± spongy in fruit, sometimes hairy, not saccate), throats funnelform, lobes 5, ± triangular (abaxially minutely crested). Cypselae obovoid to obconic or turbinate (circular or 4-angled in cross section), ribs usually 9–10 (0) and smooth or tuberculate, faces glabrous (pericarps with myxogenic cells); pappi 0 or coroniform. x = 9.
Species 175 (2 in the flora): introduced; Europe, sw Asia, n, e Africa; introduced in s Africa, Pacific Islands (New Zealand), Australia.
Anthemis secundiramea Bivona-Bernardi, a European species, was collected once in Virginia; it differs from A. arvensis in having peduncles to 8 cm and ribs on cypselae ± tuberculate.
Oberprieler, C. 2001. Phylogenetic relationships in Anthemis L. (Compositae, Anthemideae) based on nrDNA ITS sequence variation. Taxon 50: 745–762.