Smithsonian Contr. Knowl. 3(5): 122, plate 6. 1852.
Perennials, 10–30 cm (± succulent). Stems ascending to erect, branched from at or near bases. Leaves cauline; opposite; sessile; blades linear to filiform, margins entire, faces glabrous or glabrescent. Heads radiate, in tight, corymbiform arrays. Involucres campanulate, 2–3 mm diam. Phyllaries persistent, 5 in 1 series (usually yellowish, sometimes greenish, oblong to obovate, subequal, ± membranous). Receptacles flat, epaleate. Ray florets 3–5, pistillate, fertile; corollas yellow. Disc florets 5–15, bisexual, fertile; corollas yellow, tubes shorter than or equaling funnelform throats, lobes 5, ± deltate. Cypselae ± cylindric (10-ribbed); pappi persistent, usually of 5 muticous scales alternating with 5 subulate scales or coarse bristles, sometimes the 10 elements connate, forming a ± erose cup. x = 18.
sw United States, Mexico.
Species 3 (1 in the flora).