Proc. Biol. Soc. Wash. 41: 197. 1928.
Herbs. Stems ascending to erect, 15–55 cm, glabrous, glaucous. Leaves basal and cauline, ± leathery or not, glabrous, glaucous; basal and proximal cauline (15–)30–115 × 4–25 mm, blade elliptic to oblanceolate or spatulate, base tapered, margins entire, apex obtuse to acute; cauline 3–6 pairs, sessile or proximals short-petiolate, (17–)40–72 × 9–28 mm, blade ovate to lanceolate, base tapered to clasping, margins entire, apex obtuse to acute. Thyrses continuous or interrupted, cylindric, 2–21 cm, axis glabrous, verticillasters 1–6, cymes (2 or)3–8-flowered, 2 per node; proximal bracts lanceolate, 9–45 × 4–13 mm, margins entire; peduncles and pedicels erect, glabrous. Flowers: calyx lobes ovate to lanceolate, 2.5–4.5 × 1–2.4 mm, glabrous; corolla violet to blue or purple, with light violet nectar guides, funnelform, 11–15 mm, glabrous externally, sparsely whitish or yellowish pubescent internally abaxially, tube 3–4 mm, throat gradually inflated, 3.5–5 mm diam., 2-ridged abaxially; stamens: longer pair exserted, pollen sacs opposite, navicular, 0.5–0.7 mm, dehiscing completely, connective splitting, sides glabrous, sutures smooth; staminode 7–8 mm, reaching orifice, 0.2–0.3 mm diam., tip straight to slightly recurved, distal 0.5–2 mm sparsely to densely pilose, hairs golden yellow, to 0.8 mm; style 8–10 mm. Capsules 5–6 × 3.5–4.5 mm, glabrous. 2n = 48.
Phenology: Flowering Jun–Sep.
Habitat: Sandy, open pine forests, subalpine meadows.
Elevation: 1200–2400 m.
Penstemon euglaucus is a hexaploid of the Cascade Range from Three Sisters, Oregon, north to Mount Adams, Washington. A chromosome count of 2n = 16 (P. G. Zhukova 1967) is inconsistent with earlier reports of 2n = 48 (J. Clausen et al. 1940; D. D. Keck 1945) and likely is in error.