in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 667. 1836.
Annuals, 10–60 cm (herbage sweet scented). Stems (1–10) erect or ± decumbent, unbranched or sparingly branched distally, sparsely to densely pilose. Leaves cauline; alternate; petiolate; blades lanceolate, oblanceolate, ovate, or spatulate, margins entire, faces usually sparsely to moderately pilose (especially on margins), sometimes glabrate or glabrous. Heads radiate, borne singly or (2–45) in paniculiform arrays. Involucres hemispheric to globose, 12–20 mm diam. Phyllaries persistent, 17–21 in 2 series (outer usually distinct, sometimes connate proximally, green, narrowly elliptic to lanceolate, herbaceous, moderately to densely pilose, especially bases and margins; inner phyllaries distinct, obovate, hyaline, scalelike, glabrous). Receptacles globose to ovoid, ± pitted, usually epaleate (outer disc florets rarely subtended by paleae, central disc florets usually subtended by persistent enations). Ray florets 8–13(–20), pistillate, fertile; corollas yellow. Disc florets 20–50, bisexual, fertile; corollas yellow, tubes shorter than narrowly funnelform to cylindric-campanulate throats, lobes 5, ± deltate (glabrous). Cypselae narrowly obconic, prominantly 10-ribbed, densely pubescent; pappi persistent, of 5–6 ovate to obovate scales. x = 19.
Tex., n Mexico.