Syst. Bot. 16: 657. 1991.
Herbs, annual, (0.6–) 1–3 (–4) dm; with fibrous-roots. Stems solitary, erect, unbranched or branched, hairs spreading, medium length and long, soft to ± stiff, mixed with shorter stipitate-glandular ones. Leaves green to purple, linear to narrowly lanceolate, 0.5–4.2 cm, not fleshy, margins plane, flat, 0 (–5) -lobed, apex acuminate to acute; lobes ascending to erect, linear to narrowly lanceolate, apex acuminate. Inflorescences 1.5–15 × 1.5–3 cm; bracts green throughout, or proximally green, distally white to rarely cream on apices, with a tuft of erect, white, soft hairs, especially when immature, narrowly lanceolate to narrowly ovate, 3–5-lobed; lobes ascending, linear to lanceolate, long, proximal lobes arising near base, apex obtuse to acute. Calyces light green, lobes deep green, sometimes purple, 5.5–12 mm; abaxial and adaxial clefts 2.5–6.5 mm, 30–50% of calyx length, lateral 2–4.5 mm, 30–40% of calyx length; lobes linear to narrowly lanceolate or triangular, apex acuminate or acute. Corollas straight or slightly curved distally, 12–25 mm; tube 18 mm; abaxial lip and beak exserted; beak adaxially white or pale-yellow, 3.5–9 mm, hairs dense, spreading, medium length, obscuring surface; abaxial lip yellow, inflated, abruptly expanded, obpyramidal, pouches 3, central pouch slightly 2-lobed, 4–5 mm deep, 3–8 mm, 75–90% as long as beak; teeth erect, whitish to pale-yellow, 1–2 mm. 2n = 24.
Phenology: Flowering Jun–Jul.
Habitat: Springs, moist or wet meadows, flats, open forests.
Elevation: 1000–2500 m.
Most populations of Castilleja lasiorhyncha are in the San Bernardino Mountains, with a few records in the adjacent Peninsular Ranges immediately to the south. The distal tufts of soft, pale hairs on the immature bracts are apparently unique in the genus.