Proc. Amer. Acad. Arts 6: 73. 1862.
Herbs. Stems ascending to erect, (8–) 20–65 (–100) cm, glabrous or ± puberulent proximally, ± puberulent or glandular-pubescent distally, not glaucous. Leaves basal and cauline, not leathery, glabrous; basal and proximal cauline 40–90 (–130) × (5–) 10–30 (–75) mm, blade ovate to lanceolate or elliptic, base tapered to cuneate, margins entire or ± repand, denticulate, or dentate, apex obtuse to acute; cauline 2–5 pairs, short-petiolate or sessile, 25–60 (–85) × 3–15 (–25) mm, blade lanceolate to oblanceolate, base tapered to clasping or cordate-clasping, margins entire, sometimes ± repand to denticulate, apex obtuse to acute. Thyrses interrupted or continuous, secund, (2–) 5–35 cm, axis sparsely to densely glandular-pubescent, verticillasters 2–5 (–7), cymes 2–4-flowered, 2 per node; proximal bracts lanceolate, 11–85 × 1–18 mm, margins entire or ± repand proximally; peduncles and pedicels ascending to erect, glandular-pubescent. Flowers: calyx lobes lanceolate, 7–10 × 1–2.2 mm, glandular-pubescent; corolla brownish purple to bluish violet, sometimes ochroleucous, lavender, or white, with alternating white or lavender and purple nectar guides in dark-colored forms, with lavender nectar guides in light-colored forms, ventricose to ventricose-ampliate, 20–27 (–30) mm, glandular-pubescent externally, sparsely white-villous internally abaxially, tube 5–8 mm, throat abruptly inflated, 8–10 mm diam., 2-ridged abaxially; stamens included or longer pair reaching orifice, pollen-sacs opposite, explanate, 1–1.4 mm, dehiscing completely, connective splitting, sides glabrous, sutures smooth; staminode 12–15 mm, reaching orifice or exserted, 0.6–1.1 mm diam., tip straight to slightly recurved, distal 1–3 mm sparsely to densely villous, hairs yellow, to 1 mm; style 12–16 mm. Capsules 6–9 × 4–5 mm, glandular-puberulent distally. 2n = 16.
Phenology: Flowering Jun–Aug(–Sep).
Habitat: Rocky slopes in subalpine forests, alpine meadows.
Elevation: 2100–3700 m.
Ariz., Colo., Idaho, Mont., N.Mex., Utah, Wyo.
Penstemon whippleanus is known from forests and meadows of the Southern and Central Rocky mountains and westward into the Wasatch Mountains and Utah Plateaus. Plants with light-colored corollas often are found growing next to plants with dark-colored corollas.
"/4+timescorollathroat" is not declared as a valid unit of measurement for this property.