Amer. Midl. Naturalist 74: 434, fig. 4. 1965.
Herbs. Stems ascending to erect, 25–40 cm, retrorsely hairy proximally, glandular-pubescent distally, not glaucous. Leaves basal and cauline, basal sometimes withering by anthesis, not leathery, glabrous or retrorsely hairy proximally; basal and proximal cauline 25–70(–85) × 5–23 mm, blade ovate to lanceolate, base tapered, margins entire, apex acute; cauline 3–6 pairs, petiolate or sessile, 20–90(–110) × 2–18 mm, blade oblanceolate to lanceolate, base tapered, margins entire, apex acute. Thyrses interrupted, narrowly conic, 3–10 cm, axis sparsely glandular-pubescent, verticillasters 3–6, cymes 2–10-flowered, 2 per node; proximal bracts lanceolate to linear, 3–40 × 0.5–4 mm, margins entire; peduncles and pedicels ascending to erect, sparsely glandular-pubescent. Flowers: calyx lobes ovate to lanceolate, 3.5–7 × 1–2 mm, glandular-pubescent; corolla blue to light violet, with reddish purple nectar guides, funnelform, 14–19 mm, glandular-pubescent or glabrescent externally, glabrous or sparsely white- or yellow-villous internally abaxially, tube 5–6 mm, throat gradually inflated, 4–9 mm diam., slightly 2-ridged abaxially; stamens included, pollen sacs opposite, navicular, 0.9–1.1 mm, dehiscing completely, connective splitting, sides glabrous, sutures papillate; staminode 15–16 mm, included, 0.3–0.4 mm diam., tip straight to slightly recurved, distal 6–10 mm pilose, hairs golden, to 1.5 mm; style 13–16 mm. Capsules 7–10 × 2.5–4 mm, glabrous.
Phenology: Flowering Jun–Aug.
Habitat: Pine-juniper woodlands, ponderosa pine parklands, montane grasslands.
Elevation: 1800–2900 m.
Penstemon degeneri is known from the Arkansas River Canyon from near Salida to Cañon City, and to near Wet Mountain Valley. Most populations are in Fremont County (B. L. Beatty et al. 2004); the species is also known from Chaffee and Custer counties. Typical, large-leaved forms are unlikely to be confused with any other species in the area, but narrow-leaved forms can be mistaken for P. griffinii. F. S. Crosswhite (1965b) described the corollas of P. degeneri as bearded at the orifices with light yellow hairs. In most populations, the abaxial limbs and throats are sparsely yellow-lanate; however, pubescence can vary greatly within populations, from sparsely white-lanate only on the limbs to moderately yellow-lanate on the limbs and throats. When the throats are bearded in P. degeneri, the hairs extend 1–3 mm into the throats; in P. griffinii they extend deeper into the throats, usually 5–8 mm.