Pacif. Railr. Rep. 6(3): 82. 1858.
Subshrubs. Stems ascending to erect, 20–65 cm, glabrous or retrorsely hairy, hairs ± pointed, sometimes glaucous. Leaves essentially cauline, basal absent or essentially so, opposite, glabrous, sometimes glaucous distally or abaxially; cauline (3–) 6–10 pairs, petiolate or sessile, (20–) 40–80 (–105) × (2–) 4–15 mm, blade spatulate to oblanceolate or lanceolate, base tapered, margins entire, apex rounded to obtuse or acute. Thyrses interrupted, cylindric, (3–) 7–28 cm, axis glandular-pubescent, usually sparsely so proximally, verticillasters 3–6 (–9), cymes 2–4 (–7) -flowered, 2 per node; proximal bracts lanceolate to linear, 14–75 × 1–6 mm; peduncles and pedicels ascending to erect, glandular-pubescent. Flowers: calyx lobes oblong to lanceolate, 3.5–5.5 × 0.8–1.4 mm, glandular-pubescent; corolla blue to violet or purple, with or without dark blue nectar guides, funnelform, 15–20 (–24) mm, glandular-pubescent externally, glabrous internally or sparsely to densely white or yellow-pilose abaxially, tube 6–8 mm, throat gradually inflated, 4–5 mm diam., 2-ridged abaxially; stamens included or longer pair reaching orifice, filaments glabrous, pollen-sacs parallel, 1–1.3 mm, distal 1/2 indehiscent, sides glabrous, sutures denticulate, teeth to 0.1 mm; staminode 8–10 mm, included, 0.3–0.4 mm diam., distal 3–5 mm sparsely to moderately pubescent, hairs yellow, to 0.5 mm; style 12–15 mm. Capsules 5–7 × 3.5–4 mm. 2n = 16.
Phenology: Flowering Jun–Aug.
Habitat: Lava and granitic sand or gravel, sagebrush shrublands, juniper woodlands, pine-fir forests.
Elevation: 1000–3000 m.
Calif., Nev., Oreg.
Penstemon gracilentus occurs from south-central Oregon (Lake County) through northeastern California and northwestern Nevada to near Lake Tahoe. D. D. Keck (1932) hypothesized that P. gracilentus was closely related to species of sect. Penstemon; his hypothesis is supported by molecular data (A. D. Wolfe et al. 2006).
"/4+timescorollathroat" is not declared as a valid unit of measurement for this property.