Pl. Nov. Thurb., 323. 1854. 1854
Annuals, mostly 5–25 cm. Stems erect to spreading, branched from bases. Leaves mostly basal; subopposite or alternate; petiolate; blades ± deltate to elliptic, sometimes 3-lobed, ultimate margins ± serrate, faces sparsely hirsute or glabrate. Heads radiate, borne singly. Involucres turbinate to hemispheric, mostly 7–9 mm diam. Receptacles convex, knobby, epaleate. Phyllaries 8–22 in 2–3 series (lanceolate to linear, unequal, glandular-puberulent and sparsely strigose). Ray florets 5–13, pistillate, fertile; corollas golden yellow. Disc florets 30–90, bisexual, fertile; corollas yellow, sometimes suffused with purple, tubes (slender) longer than funnelform throats, lobes 5, spreading, deltate (style-branch apices truncate, penicillate). Cypselae obcompressed (each shed with subtending, linear, membranous scale, scales sometimes interpreted as paleae), margins ciliate; pappi fragile, of 17–22 bristles. x = 11.
sw United States, Mexico.