Edwards’s Bot. Reg. 15: plate 1270. 1829. (as Pentstemon speciosum)
Stems decumbent to ascending or erect, 7–65(–90) cm, glabrous or retrorsely hairy to pubescent, not glaucous. Leaves basal and cauline, basal sometimes absent, ± leathery or not, glabrous or retrorsely hairy, not glaucous; basal and proximal cauline (25–)30–90(–140) × (3–)6–20(–35) mm, blade oblanceolate to elliptic or lanceolate, base tapered, margins entire, apex obtuse to acute; cauline 3–8 pairs, short-petiolate or sessile, 35–70(–150) × 3–20(–30) mm, blade oblanceolate to elliptic, lanceolate, or linear, base tapered to clasping, apex obtuse to acute. Thyrses continuous, secund or cylindric, (1–)3–35 cm, axis glabrous or puberulent, rarely glandular or glandular-pubescent, verticillasters (2–)4–14, cymes 1–4-flowered, 2 per node; proximal bracts lanceolate, rarely ovate or linear, (15–)20–80 × (1–)2–23 mm; peduncles and pedicels ascending to erect, glabrous or retrorsely hairy, rarely glandular-pubescent, peduncles to 20 mm, pedicels 1–8 mm. Flowers: calyx lobes ovate to lanceolate, rarely obovate, (4–)6–11(–13.5) × 2–4 mm, margins erose, apex acute to acuminate or cuspidate, glabrous or ± glandular proximally; corolla blue to violet, with reddish purple nectar guides, ventricose, 25–35 mm, glabrous externally, glabrous, rarely sparsely white-pilose, internally abaxially, tube 8–13 mm, throat gradually inflated, slightly constricted at orifice, 7–10(–13) mm diam., 2-ridged abaxially; stamens: longer pair reaching orifice, pollen sacs divergent, sigmoid, (1.8–)2–3 mm, dehiscing incompletely, proximal 1/3 indehiscent, connective not splitting, sides glabrous or sparsely hispidulous, hairs tan, to 0.3 mm, sutures papillate or denticulate, teeth to 0.1 mm; staminode 14–18 mm, included, 0.6–1 mm diam., tip straight to recurved, glabrous or distal 1–7 mm sparsely pilose, hairs yellow to yellowish orange, to 0.8 mm; style 18–23 mm. Capsules 10–16 × 6–8 mm. 2n = 16.
Phenology: Flowering May–Aug(–Sep).
Habitat: Sagebrush shrublands, pinyon-juniper woodlands, clearings in pine forests.
Elevation: 300–3300 m.
Calif., Idaho, Nev., Oreg., Utah, Wash.
Penstemon speciosus is widespread and highly polymorphic. F. S. Crosswhite (1967b) examined morphologic variation and concluded it was clinal.