Rhodora 36: 187. 1934. (as unalaschkensis)
Herbs, perennial, 2–8 dm; from a short, stout, scaly, many-headed, woody caudex; with rhizomes or branching, woody roots. Stems few to many, erect to ascending, unbranched or branched distally, glabrate proximally, hairy distally, hairs sparse, spreading to erect, long, soft, eglandular, rarely stipitate-glandular. Leaves green, sometimes red-purplish, lanceolate-linear to lanceolate, elliptic-ovate, or ovate, (1.2–)3.5–10 cm, not fleshy, margins plane, sometimes ± wavy, flat to slightly involute, 0(–3)-lobed, apex acuminate to acute; lobes ascending, lanceolate, apex acute to acuminate. Inflorescences 3.5–18 × 2–6.5 cm; bracts proximally green, distally yellow, pale yellow, whitish, yellow-green, or pale orange, often aging reddish or pink, lanceolate, elliptic, ovate, oblanceolate, or oblong to narrowly obovate, (0–)3–5-lobed; lobes ascending, linear to oblong, short, arising above mid length, apex acute to obtuse. Calyces colored as bracts, 15–28 mm; abaxial cleft 12–16 mm, adaxial 8–11.5 mm, clefts 40–50% of calyx length, deeper than laterals, lateral 4–10 mm, 20–35% of calyx length; lobes oblong to lanceolate, apex acute to obtuse or rounded. Corollas straight or slightly curved, 18–28 mm; tube 16–19 mm; beak partially to completely exserted, abaxial lip not exserted; beak adaxially green, 6–13 mm; abaxial lip deep green, reduced, inconspicuous, 1–2 mm, ca. 20% as long as beak; teeth incurved, deep green or white, 0.5–1 mm. 2n = ca. 96.
Phenology: Flowering May–Sep.
Habitat: Meadows, dunes, thickets, upper margins of tidal flats, river flats, gravel bars, tundra, open forests, roadsides, coastal to alpine.
Elevation: 0–2100 m.
B.C., Yukon, Alaska, Asia (Russian Far East).
Castilleja unalaschcensis is a characteristic meadow species across much of the southern Alaskan coast, including the Aleutian Islands, as well as on the Queen Charlotte Islands (Haida Gwaii) and the mainland of western British Columbia and southern Yukon. It is common in the coastal littoral zone and ascends to lower alpine meadow communities. Morphologically, it appears to be a sister species to C. septentrionalis of the Rocky Mountains and boreal sites in eastern North America. A weakly differentiated interior form was described as subsp. transnivalis Pennell.