Hymenatherum concinnum A. Gray in A. Gray et al., Syn. Fl. N. Amer. 1(2): 446. 1884; Dyssodia concinna (A. Gray) B. L. Robinson

Annuals, green, 3–12+ cm, glabrous. Stems spreading to ascending or erect. Leaves alternate; blades 10–15 mm overall, lobed, lobes (3–)5–9, linear to filiform. Peduncles 1–5+ mm, glabrous. Calyculi 0, or of 1–2 subulate bractlets, lengths less than ¹/2 phyllaries. Involucres obconic to campanulate, 5–6.5 mm. Phyllaries 8–16, margins of outer distinct less than ¹/2 their lengths, abaxial faces glabrous. Ray florets 9–12; corollas white to pale yellow, laminae 3–4 × 1–3.5 mm. Disc florets ca. 25; corollas pale yellow, 3–4.5 mm. Cypselae 2.5–3 mm; pappi of 10–15 scales (each comprising 5–9 basally connate bristles) 1–2.5 mm. 2n = 16.

Flowering spring, following rains. Sandy washes and flats, in deserts; 50–100 m; Ariz.; Mexico (Sonora).