Gen. Hist. 4: 615. 1837/1838.
Herbs, perennial, 1.5–3 (–4) dm; from a woody caudex; with a taproot. Stems few-to-many, erect to ascending, branched, sometimes unbranched, hairs fairly dense, spreading to appressed, white, fairly short, soft, ± felty, eglandular, sometimes mixed sparsely with short-stipitate-glandular ones, sometimes obscuring surface. Leaves green to purple, linear to narrowly oblong-lanceolate, 2–7 (–9) cm, not fleshy, margins plane, sometimes slightly wavy, involute, 3–7-lobed, apex narrowly acute to rounded; lobes spreading, linear, apex obtuse or acute. Inflorescences 2.6–16 × 2–4 cm; bracts proximally greenish to deep greenish purple, distally purple, magenta, reddish, pink, or rose, rarely white, cream, light yellow, or dull orangish, proximal linear to lanceolate, distal oblong, 3–7 (–9) -lobed; lobes spreading to ascending, linear to oblanceolate, long, arising from distal 2/3, center lobe apex obtuse to rounded, lateral ones acute to rounded. Calyces colored as bracts, (20–) 25–34 mm; abaxial and adaxial clefts (10–) 13–22 mm, 50–60% of calyx length, deeper than laterals, lateral 7–16 mm, 35–45% of calyx length; lobes broadly linear to long-triangular or oblong, apex acute to obtuse. Corollas slightly curved, 25–40 mm; tube 16–22 mm; beak exserted, adaxially green, 9–18 mm; abaxial lip green to purple-red, reduced, not strongly pouched, ± protruding, 4–5 mm, 33–50% as long as beak; teeth prominent, petaloid, spreading to erect, colored as in distal portion of bracts, 3–4 mm.
Phenology: Flowering Mar–May.
Habitat: Rocky slopes, ledges, prairies, woodlands, thickets, roadsides, often sandy or limy soils.
Elevation: 200–600 m.
Kans., Mo., Okla., Tex.
Castilleja purpurea is a common species of eastern Oklahoma and central Texas, with a few records from adjacent southeastern Kansas and southwestern Missouri. It often provides beautiful, multicolored displays in the meadows within its range. Castilleja citrina and C. lindheimeri are closely related species sometimes regarded as varieties of C. purpurea. Hybrids and hybrid swarms between C. indivisa and C. purpurea have been observed at some localities where they are sympatric.