Bristleleaf Pricklyleaf

Annuals (rarely persisting), green, to 30 cm, glabrous or sparsely hirtellous. Stems decumbent to erect. Leaves mostly alternate (sometimes opposite at 1–3 proximal nodes); blades usually lobed, 12–28 mm overall, lobes 7–15, linear to filiform, pliable (blades mostly not lobed in var. wrightii. Peduncles 30–80 mm, glabrous or hirtellous. Calyculi of 3–8 deltate to subulate bractlets, lengths less than ¹/2 phyllaries. Involucres obconic, 5–7 mm. Phyllaries 12–22, margins of outer distinct less than ¹/5 their lengths, abaxial faces glabrous or sparsely hirtellous. Ray florets 10–21; corollas yellow-orange, laminae 4–10 × 1.5–3 mm. Disc florets 50–100+; corollas yellow, 2.5–4.5 mm (peripheral ± zygomorphic in some plants). Cypselae 2–3.5 mm; pappi of erose and/or aristate scales 0.7–3.5 mm.

Hymenatherum tenuilobum de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 462. 1836; Dyssodia tenuiloba (de Candolle) B. L. Robinson