Bot. Gaz. 41: 322. 1906. (as Castilleia)
Herbs or subshrubs, perennial, 3–8 dm; from a woody caudex; with woody, branching roots. Stems few to many, ascending to erect, much-branched, usually with prominent leafy axillary shoots, hairs spreading, long, soft, mixed with shorter, stipitate-glandular ones. Leaves green-tinged or ± purple, sometimes yellow-green tinged, densely crowded, linear, lanceolate, oblong, elliptic, or ovate, 1–7 cm, thickened, not usually fleshy, margins plane to wavy, involute or flat, 0–3(–5)-lobed, apex broadly rounded to obtuse or acute; lobes spreading-ascending, linear, narrowly lanceolate, triangular, or rounded, apex acute, obtuse, or rounded. Inflorescences 3–22 × 1.5–3.5 cm; bracts proximally green to deep purple, rarely light tan, distally red, scarlet, rose, red-orange, or yellow, sometimes orange, dull brownish orange, pale pinkish tan, yellow aging white, yellow aging pink, red with pink apices, magenta, or white, sometimes with a yellow to deep purple medial band, lanceolate, oblong, or narrowly ovate, (0–)3–5(–7+)-lobed, distal margins of central lobe and sometimes also side lobes with multiple shallow teeth, proximal often wavy-margined; lobes erect or ascending, linear to lanceolate or oblanceolate, short, arising in distal 2/3, apex obtuse to acute, central lobe often rounded to truncate. Pedicels 0 mm or nearly so. Calyces colored as bracts, 15–28 mm; abaxial and adaxial clefts 8–11 mm, 33–50% of calyx length, deeper than laterals, lateral 2–5.5 mm, 5–30% of calyx length; lobes lanceolate to oblong to broadly triangular, apex acute, obtuse, or rounded. Corollas slightly curved proximally, 20–30 mm; tube 10–12 mm; distal portion of beak exserted, abaxial lip included; beak adaxially green to yellow, 11.5–18 mm; abaxial lip deep green, sometimes to very deep purple, reduced, included, usually not visible through front cleft, 1–2 mm, 15–25% as long as beak; teeth erect, green to sometimes pink, 0.5–1.5 mm. 2n = 24, 48.
Phenology: Flowering Mar–Aug(–Nov).
Habitat: Coastal scrub, damp thickets, stream banks, sea bluffs, canyon slopes, roadsides.
Elevation: 0–700 m.
Castilleja wightii is found along or near the central and northern coast of California. Historical collections of C. wightii from Curry County, Oregon, are referable to other species, but it should be sought in the area. Reports from the south-central coast of California are referable to other species, particularly C. affinis. Castilleja wightii appears to intergrade with C. latifolia and perhaps C. affinis south of San Francisco. Despite much attention from botanists, the perennial paintbrushes along the coast between Monterey and San Francisco can be perplexing and difficult to identify. This situation is likely the result of introgression, but this complex is in need of meticulous genetic and morphological analysis. North of San Francisco, C. wightii is straightforward to recognize, with its abundantly stipitate-glandular stems and leaves. In addition, the leaves are often crowded on the stems, which bear axillary shoots. Most populations have either red or yellow bracts, with only occasional individual plants of the other color. Yellow populations are found primarily in Marin and southern Sonoma counties southward and are gradually replaced by red populations from northern Sonoma County northward. Mixed color populations occur in a few places, especially in San Mateo County.