Proc. Amer. Acad. Arts 44: 574. 1909.
Herbs or subshrubs, perennial, 3–6(–10) dm; from a woody caudex; with a taproot. Stems solitary or few, ascending to erect, straight, unbranched or branched, hairs dense, spreading, long, stiff, eglandular, mixed with deflexed, short stipitate-glandular ones. Leaves green to purple-tinged, linear-lanceolate to broadly lanceolate or oblanceolate, 1.5–8 cm, not fleshy, margins plane, involute, 0-lobed, apex rounded to acute. Inflorescences 3–16 × 2–4.5 cm; bracts proximally green to deep purple, distally red to red-orange or orange, sometimes with a pale medial band, lanceolate to oblanceolate to ovate or obovate, 0(–3)-lobed; lobes when present upright, ± triangular, short, arising from distal portion, apex obtuse to rounded or truncate. Calyces proximally light green, distally deep green, deep purple, or blackish, 15–24 mm; abaxial and adaxial clefts 5–9 mm, 25–45% of calyx length, deeper than laterals, lateral 0–0.5 mm, 0–3% of calyx length; lobes oblong, sometimes emarginate, apex obtuse, rounded, or obliquely truncate. Corollas straight, 15–24 mm; tube 11–13 mm; subequal to calyx or tip slightly exserted; beak adaxially whitish to pinkish, 5–11 mm; abaxial lip pale to deep green, reduced, 1–2 mm, 10–20% as long as beak; teeth incurved, green, 1–2.5 mm. 2n = 24, 48.
Phenology: Flowering Aug–Sep.
Habitat: Dry south-facing rocky slopes with scattered bunchgrasses and oaks, cliff bases, mesa tops, open pine-oak woodlands, rocky savannas.
Elevation: 1800–2400 m.
Ariz., Mexico (Aguascalientes, Chihuahua, Colima, Durango, Guerrero, Jalisco, México, Michoacán, Morelos, Nayarit, Oaxaca, Puebla, Sonora, Veracruz).
Castilleja nervata is a common and widespread Mexican species, from northern Chihuahua and Sonora south to central Oaxaca. It has medicinal value to indigenous peoples of the Sierra Madre. In the flora area, C. nervata is known from a single, presumably extant population in the Chiricahua Mountains in Cochise County, though there are historical records from the Rincon and Santa Rita mountains. The sole recently verified population is on private property and is endangered.