in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 112. 1859. (as Pentstemon)
Stems 20–90 cm, retrorsely hairy, sometimes glabrescent. Leaves glabrous or retrorsely hairy; basal and proximal cauline 16–80 × 3–10 mm, blade oblanceolate to lanceolate, base tapered, margins entire, apex obtuse to acute; cauline 6–15(–20) pairs, 45–150 × 1–6 mm, blade linear, base tapered, apex acute to acuminate. Thyrses cylindric to ± secund, 10–35 cm, axis glabrous, verticillasters (2–)5–8, cymes (1 or)2–4(or 5)-flowered; proximal bracts linear, 8–30(–80) × 0.5–2 mm; peduncles and pedicels glabrous or pedicels rarely glandular-pubescent. Flowers: calyx lobes elliptic to ovate, 4.2–7(–8.5) × 2–2.6(–3.5) mm, glabrous, rarely glandular-pubescent; corolla violet to blue, lavender, or purple, lined internally abaxially with reddish purple nectar guides, ventricose, 23–37 mm, glabrous internally, tube 7–10 mm, throat abruptly inflated, 9–10 mm diam., slightly 2-ridged abaxially; stamens included, pollen sacs parallel to divergent, 1.6–1.8 mm, sutures denticulate, teeth to 0.2 mm; staminode 20–23 mm, exserted, 1.8–2.6 mm diam.; style 20–24 mm. Capsules 9–15 × 6–9 mm.
Phenology: Flowering Jul–Oct.
Habitat: Desert grasslands, openings in pine and pine-oak woodlands.
Elevation: 1200–1700 m.
Ariz., Mexico (Chihuahua, Durango, Sonora, Zacatecas).
In the flora area, Penstemon stenophyllus is known from the Huachuca and Patagonia mountains in Cochise and Santa Cruz counties. In Mexico, populations occur primarily along the Sierra Madre Occidental southward to central Durango at elevations to 2300 m.