Herbs. Stems ascending to erect, 20–50(–65) cm, glabrous or retrorsely hairy, not glaucous. Leaves basal and cauline, basal often poorly developed, not leathery, glabrous; basal and proximal cauline 20–75 × 2–5(–7) mm, blade narrowly elliptic to linear, base tapered, margins entire, apex obtuse to acute; cauline 5–8 pairs, sessile or proximals long-petiolate, 15–75 × 2–8 mm, blade lanceolate to linear, base tapered, margins entire, apex acute. Thyrses interrupted or continuous, cylindric, 3–25 cm, axis glandular-pubescent, verticillasters 2–6(–10), cymes 1–7-flowered, 2 per node; proximal bracts lanceolate, 6–55 × 1–8 mm, margins entire; peduncles and pedicels erect, glandular-pubescent. Flowers: calyx lobes obovate to ovate or lanceolate, 1.5–3 × 0.7–1.5 mm, glandular-pubescent; corolla violet to light blue, pink, or light purple, with or without pink or purple nectar guides, tubular to tubular-funnelform, 8–10 mm, glandular-pubescent externally, moderately yellow-pilose internally abaxially, tube 3–4 mm, throat slightly inflated, 2–3 mm diam., slightly 2-ridged abaxially; stamens included, pollen sacs opposite, navicular to subexplanate, 0.4–0.5 mm, dehiscing completely, connective splitting, sides glabrous, sutures smooth; staminode 4–6 mm, included, 0.3–0.4 mm diam., tip straight, distal 0.3–0.5 mm sparsely pilose, hairs yellow, to 0.4 mm; style 7–8 mm. Capsules 3.5–5 × 2–3 mm, glabrous. 2n = 32.
Phenology: Flowering Jun–Aug.
Habitat: Dry, sandy, volcanic soils, pine forests.
Elevation: 900–1500 m.
Penstemon peckii is known from the eastern slope of the Cascade Range in Crook, Deschutes, Hood River, and Jefferson counties.