1. Malacothrix californica de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 7: 192. 1838.
Annuals, 4–45 cm. Stems 1 (scapiform), erect or arcuate-ascending, mostly glabrous (shaggily piloso-hirsute proximally and at bases of heads). Cauline leaves: proximal oblanceolate to linear, pinnately lobed (lobes usually linear to filiform, sometimes broader), not fleshy, ultimate margins entire or dentate, faces usually shaggily piloso-hirsute (at least proximally), glabrescent; distal usually 0. Calyculi of 12–20, lanceolate to linear bractlets, hyaline margins 0.05–0.2 mm, abaxial faces shaggily piloso-hirsute to arachnose. Involucres (8–)10–15 × 5–6 mm. Phyllaries usually 20–26+ in 2-3+ series, (midstripes often reddish) lanceolate to lance-linear or subulate, unequal, hyaline margins 0.1–0.5 mm wide, abaxial faces (of outermost, at least) shaggily piloso-hirsute to arachnose (at least proximally). Receptacles sparsely bristly or glabrous. Florets 40–250; corollas usually yellow to pale yellow (often with abaxial reddish stripes), sometimes white, 16–20 mm; outer ligules exserted 11–13 mm. Cypselae ± prismatic, 2–3.4 mm, ribs extending to apices, 5 more prominent than others; persistent pappi of 12–15+, irregular, lance-deltate teeth plus (1–)2 bristles. Pollen 70–100% 3-porate. 2n = 14.
Flowering Apr–Jun. Open sandy soil in grasslands, oak woodlands, chaparral, or desert margins; 0–1700 m; Calif.; Mexico (Baja California).
Malacothrix californica grows in the San Joaquin Valley, central western California, southwestern California, and the Mojave Desert.