Bot. Gaz. 62: 147. 1916.
Stems ascending to erect, (15–) 30–70 cm, glabrous, not glaucous. Leaves basal and cauline, leathery or not, glabrous, not glaucous; basal and proximal cauline 80–140 (–180) × (10–) 15–35 (–40) mm, blade ovate to elliptic, base tapered, margins entire, apex obtuse to acute; cauline 5–7 pairs, sessile, (28–) 40–80 (–110) × 6–30 (–42) mm, blade ovate to lanceolate, base tapered to cordate-clasping, apex acute. Thyrses continuous, sometimes interrupted proximally, cylindric, (3–) 8–32 cm, axis glabrous, verticillasters 4–10 (–16), cymes 2–4 (–8) -flowered, 2 per node; proximal bracts ovate to lanceolate, 12–80 × 2–35 mm; peduncles and pedicels glabrous. Flowers: calyx lobes lanceolate, 5–8.5 (–10) × 1–2 mm, glabrous; corolla blue to violet, without nectar guides, ventricose, 18–22 mm, glabrous externally, glabrous internally, tube 6–9 mm, throat gradually inflated, not constricted at orifice, 7–10 mm diam., slightly 2-ridged abaxially; stamens: longer pair reaching orifice or slightly exserted, pollen-sacs opposite, navicular, 1.2–1.9 mm, dehiscing incompletely, connective not splitting, sides glabrous, sutures denticulate, teeth to 0.1 mm; staminode: 13–15 mm, included, 0.5–0.9 mm diam., tip straight, distal 2–3 mm sparsely pilose, sometimes glabrous, hairs yellow, to 0.5 mm; style 13–17 mm. Capsules 8–15 × 5–8 mm. 2n = 16.
Phenology: Flowering May–Aug.
Habitat: Gravelly sagebrush shrublands, open coniferous forests.
Elevation: 1200–2600 m.
Idaho, Mont., Oreg.
Penstemon payettensis is known from the Northern Rocky Mountains and eastern Columbia Plateau.
"/4+timescorollathroat" is not declared as a valid unit of measurement for this property.