Mem. Amer. Acad. Arts, n. s. 4: 103. 1849.
Plants 3–70 cm (self-incompatible); glandular, not strongly scented. Stems usually not purple-streaked. Leaf blades lanceolate or oblanceolate to linear, 4–100(–120) mm, margins (basal leaves) toothed to pinnatifid. Involucres hemispheric, 4–18 × 4–15+ mm. Phyllaries 5–18, apices often longer (sometimes shorter) than folded bases. Paleae in 1 series between ray and disc florets. Ray florets 5–18; laminae yellow or proximally yellow and distally white, 3–21 mm. Disc florets 6–120+; corollas 3.5–6 mm; anthers ± dark purple (in southwest of range, sometimes yellow or brownish). Ray cypselae glabrous or sparsely hairy. Disc pappi 0 or of 14–32 white to tawny, ± equal bristles or setiform scales 2–5 mm, each ± scabrous, usually not plumose and not adaxially woolly (in southwest of range, often proximally plumose and adaxially woolly). 2n = 14.
Phenology: Flowering Feb–Jul.
Habitat: Open, often grassy slopes or flats, disturbed sites, often on sandy or clayey soil, sometimes serpentine
Elevation: 0–2000 m
Calif., Mexico (Baja California).
Layia platyglossa occurs from the North Coast Ranges through central-western and southwestern California and west to the immediate coast and east into the central Great Valley. A specimen reported by S. L. Welsh et al. (1993) from dunes in Utah (Harrison 2545, BRY) may be mislabeled.