Contr. U.S. Natl. Herb. 20: 359. 1920
Stems ascending to erect, 14–40(–60) cm, glabrous. Leaves basal and cauline, glabrous; basal and proximal cauline 40–65(–110) × 8–20(–30) mm, blade obovate, base tapered, apex obtuse to acute, sometimes mucronate; cauline 2–4 pairs, sessile, (9–)12–60 × 7–26 mm, blade lanceolate to ovate or elliptic, base tapered to clasping or cordate-clasping, apex obtuse to acute, sometimes mucronate. Thyrses interrupted or ± continuous, secund, sometimes cylindric, 5–23 cm, axis glabrous, verticillasters 4–8, cymes 1–3(or 4)-flowered; proximal bracts ovate to lanceolate, (3–)7–38 × (1–)2–18 mm; peduncles and pedicels glabrous, peduncles to 28 mm. Flowers: calyx lobes ovate to lanceolate, 5–6.7(–7.2) × 2–3(–3.7) mm, margins entire or erose, broadly scarious, glabrous; corolla lavender to violet, blue, pinkish blue, or white, with or without reddish violet nectar guides, tubular-funnelform, 17–20(–22) mm, glabrous externally, sparsely white-villous internally abaxially or glabrous, tube 5–8 mm, throat gradually inflated, 5–6 mm diam., rounded abaxially; stamens included or longer pair reaching orifice, pollen sacs opposite, 1.1–1.6 mm, sutures papillate; staminode 8–9 mm, reaching orifice or slightly exserted, 0.6–1 mm diam., tip strongly recurved, distal 3–4 mm sparsely to densely villous, hairs mostly along margins, yellowish, to 1 mm; style 10–12 mm. Capsules 9–12 × 5–7 mm. Seeds 3.5–5 mm.
Ariz., Colo., N.Mex., Utah
Varieties 2 (2 in the flora).
Penstemon lentus is found in the Four Corners region of the Colorado Plateau. Reported differences (N. H. Holmgren 1984) between the two varieties in the sizes of the pollen sacs appear to be inconsistent and not taxonomically useful.