Brittonia 51: 445, fig. 1. 1999.
Herbs, perennial, 1.5–3.7 dm; from a thick, woody caudex; with a taproot. Stems solitary or few to several, ascending, sometimes short-decumbent and rooting, branched from near base, sometimes distally, glabrous or glabrate with hairs very sparse, ± appressed, very short, soft, eglandular. Leaves green, often brown or purple-tinged, oblong to lanceolate to narrowly ovate or ovate, (1–) 2–5.8 cm, not fleshy, margins plane, ± involute, deeply 3–7 (–11) -lobed, sometimes with secondary lobes, apex narrowly acute; lobes erect to ascending, lanceolate to linear-lanceolate to oblanceolate, apex acute. Inflorescences 3–15 × 2–4.5 cm; bracts proximally greenish, distally bright red, scarlet, or pale reddish orange, rarely orange-yellow, often fading to pale yellowish orange with age, obovate to orbicular, fan-shaped, (3–) 5–9 (–13) -lobed, sometimes with secondary lobes; lobes erect or ascending, lanceolate to triangular, short and medium length, usually arising at or above mid length, rarely below, apex acute. Calyces proximally green, sometimes purple to brown, distally colored as bracts, 20–30 mm; abaxial and adaxial clefts 7–14 mm, ca. 33% of calyx length, deeper than laterals, lateral 2–4 mm, 10–15% of calyx length; lobes triangular, barely longer than wide, apex acute or acuminate to obtuse. Corollas straight, 30–45 mm; tube 14–19 mm; beak long-exserted, adaxially green or yellow-green to brownish, 18–24 mm; abaxial lip deep green, reduced, 1–3 mm, 10% as long as beak; teeth incurved, greenish to dull purplish, 0.5–1.5 mm. 2n = 24.
Phenology: Flowering Jun–Aug.
Habitat: Turf or crevices on rocky slopes and benches over basalt, se to sw aspect, sun or partial shade.
Elevation: 600–1000 m.
Castilleja chambersii is limited to the summits of three volcanic peaks in the northern Coast Range of Clatsop County, Oregon, and at one similar area in nearby Pacific County, Washington. It is similar to C. rupicola, and the two likely share a common ancestor. Disturbance and erosion from logging and road construction represent significant threats to C. chambersii. Populations of C. chambersii often grow near and even alongside C. hispida, but hybrids are rare.
"acute" is not a number."medium" is not a number.