Castilleja christii
Bull. Torrey Bot. Club 100: 91, fig. 5. 1973.
Herbs, perennial, 1.4–3 dm; from a woody caudex; with a taproot. Stems several, erect to ascending, unbranched, sometimes branched, glabrous or hairs spreading, short and long, ± stiff, sometimes stipitate-glandular especially distally. Leaves green, narrowly to broadly lanceolate, (1–) 2–5 (–6) cm, not fleshy, margins plane, flat or involute, (0–) 3 (–5) -lobed, apex acute to rounded; lobes erect or ascending, linear, lanceolate, or triangular, sometimes very small, apex acute to rounded. Inflorescences 3–6 × 2–4 cm; bracts proximally greenish, distally pale orange or pale-yellow, sometimes red-orange, lanceolate or narrowly elliptic to ovate, sometimes obovate, 3–5-lobed; lobes ascending, linear, medium length to long, arising at or below mid length, apex acute to obtuse. Calyces colored as bracts, 17–22 (–24) mm; abaxial clefts 9–12 (–13) mm, adaxial 7–11 mm, clefts 50% of calyx length, deeper than laterals, lateral 2–6.5 (–8.5) mm, 20–50% of calyx length; lobes lanceolate to narrowly lanceolate, apex acute to obtuse. Corollas straight, 20–30 mm; tube 12–19 mm; beak exserted, adaxially green, 7–12 mm; abaxial lip green, reduced, included or visible through cleft, 1.5–2 mm, 10–20% as long as beak; teeth incurved, deep green, 1.5 mm.
Phenology: Flowering Jun–Jul.
Habitat: Gentle slopes, mostly northern aspect, in herbaceous or grassy subalpine to alpine meadows, sagebrush openings and swales, snowbank communities, over quartzite.
Elevation: 2100–2900 m.
Discussion
Castilleja christii is endemic to subalpine meadows near the summit of Mt. Harrison in the Albion Mountains, Cassia County. Morphologically, it most closely resembles the widespread C. hispida var. acuta, but a recent molecular study (D. L. Clay et al. 2012) presents clear evidence for a homoploid hybrid origin for the species, incorporating portions of the genomes of C. linariifolia and C. miniata. This is the first documented case of homoploid origin in Castilleja.
Castilleja christii is in the Center for Plant Conservation’s National Collection of Endangered Plants.
Selected References
None.