Anthemis spp.
Family: Asteraceae
Project: Southwest Biodiversity Consortium
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. 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.

Species
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