A. Gray

in A. Gray et al., Syn. Fl. N. Amer. ed. 2, 1(2): 448. 1886.

Etymology: Greek dimeres, in 2 parts or with 2 members, allusion unclear
Treatment appears in FNA Volume 21. Treatment on page 182. Mentioned on page 364, 401.

Annuals, 1–3(–5) cm. Stems decumbent to erect. Leaves basal and/or cauline; opposite (crowded, seemingly whorled); subsessile or ± petiolate; blades spatulate to oblanceolate, entire. Heads discoid, in clusters (of 2–5, congested, total heads to 100+). Involucres cylindric to obconic, 2(–4) mm diam. Phyllaries 2(–3) in 1 series (basally distinct or connate, oblong, herbaceous). Ray florets 0. Disc florets 2(–3), bisexual, fertile; corollas white, pink, or purple, tubes slightly shorter than funnelform throats, lobes 5, deltate-ovate. Receptacles minute, epaleate. Cypselae cylindric to clavate, striate, glabrous; pappi falling, of ca. 20 basally connate, setiform to subulate, ± plumose scales (or flattened bristles). x = 7.


w United States.


Species 1.

Selected References


Lower Taxa