Stems ascending, 30–100(–150) cm, pubescent, hirsute, glabrescent, puberulent, sparsely hispid, or downy. Leaves puberulent and often hirsute; proximal 10–40 mm, margins 3-lobed, lobes 1–3 mm wide; distal 10–30 × 0.5–1.5 mm, margins entire or 3-lobed. Inflorescences capitate spikes, 2–15-flowered; bracts 5–10, 5–20 mm, margins entire or 3-lobed, lobes purplish black, ivory, or green distally, linear-lanceolate to linear or slightly spatulate. Pedicels: bracteoles 14–20 mm, margins entire or toothed. Flowers: calyx 10–20 mm, tube 1–2 mm, apex entire or 2-fid, cleft 0–1 mm; corolla pale yellow with purple veins and an abaxial, U-shaped, purple mark, 8–20 mm, throat 5–10 mm diam., abaxial lip 6–10 mm, ca. equal to and appressed to adaxial; stamens 4, filaments hairy, fertile pollen sacs 2 per filament, subequal. Capsules oblong-ovoid, 8–12 mm. Seeds 10–25, dark brown, oblong-ovoid, 1.5–2 mm, striate. 2n = 28.
Calif., nw Mexico.
Subspecies 4 (4 in the flora).
Cordylanthus rigidus is variable, with many locally distinctive populations that intergrade with each other and with nearby species.
|1||Proximal bracts 5–12 mm, shorter than flowers.||Cordylanthus rigidus subsp. brevibracteatus|
|1||Proximal bracts 10–20 mm, equal to or longer than flowers.||> 2|
|2||Proximal bracts: midlobes linear, 0.5–1 mm wide, dark purple distally.||Cordylanthus rigidus subsp. setigerus|
|2||Proximal bracts: midlobes linear-lanceolate or lanceolate, 1–2.5 mm wide, green or red distally.||> 3|
|3||Stems pubescent and hirsute, hairs stiff; proximal bracts: midlobe apices retuse.||Cordylanthus rigidus subsp. rigidus|
|3||Stems downy to puberulent, hairs soft; proximal bracts: midlobe apices acute to retuse.||Cordylanthus rigidus subsp. littoralis|