Edwards’s Bot. Reg. 15: plate 1295. 1830. (as Pentstemon attenuatum)
Herbs. Stems ascending to erect, (2–)5–70(–90) cm, glabrous or retrorsely hairy, not glaucous. Leaves basal and cauline, not leathery, glabrous or puberulent; basal and proximal cauline (30–)55–90(–150) × 5–20(–40) mm, blade spatulate to obovate or elliptic, base tapered, margins entire, rarely denticulate, apex rounded to obtuse or acute; cauline 2–5(–7) pairs, sessile or proximals short- to long-petiolate, 15–90(–130) × 2–25(–38) mm, blade usually lanceolate, proximals sometimes oblanceolate, base tapered to clasping, margins entire, rarely serrate or dentate, apex acute, sometimes obtuse. Thyrses interrupted, cylindric, 3–27 cm, axis moderately glandular-pubescent, verticillasters 2–7, cymes (1 or)2–8-flowered, 2 per node; proximal bracts lanceolate, 15–55(–80) × 2–15(–28) mm, margins entire or ± serrate to dentate; peduncles and pedicels erect, glandular-pubescent. Flowers: calyx lobes ovate to obovate, ovate-oblong, or lanceolate, 3.2–7.5 × 0.9–2.6 mm, margins erose or lacerate, apex acuminate to short-caudate or long-acuminate, glandular-pubescent; corolla light blue to violet, bluish purple, or pinkish blue, rarely light yellow or whitish, with reddish purple nectar guides, tubular-funnelform, 7–20 mm, glandular-pubescent externally, moderately white-lanate internally abaxially, tube 4–5 mm, throat slightly inflated, 3–5(–6) mm diam., 2-ridged abaxially; stamens included, pollen sacs opposite, navicular to slightly saccate, 0.6–1.2 mm, dehiscing completely or incompletely, distal 1/5 or less sometimes indehiscent, connective splitting or not, sides glabrous, sutures smooth or papillate; staminode 7–9 mm, reaching orifice or slightly exserted, 0.3–0.4 mm diam., tip straight to slightly recurved, distal 1–3 mm ± pilose, hairs yellow, to 1.2 mm; style 8–12 mm. Capsules 4–8 × 2–5 mm, glabrous. 2n = 48.
Idaho, Mont., Oreg., Wash., Wyo.
Varieties 4 (4 in the flora).
|1||Pollen sacs dehiscing incompletely, distal 1/5 or less usually indehiscent, connectives not splitting, sutures papillate.||Penstemon attenuatus var. militaris|
|1||Pollen sacs dehiscing completely, connectives splitting, sutures smooth, sometimes ± papillate.||> 2|
|2||Corollas 7–12 mm; calyx lobes lanceolate.||Penstemon attenuatus var. palustris|
|2||Corollas 12–20 mm; calyx lobes ovate, obovate, ovate-oblong, or lanceolate.||> 3|
|3||Stems (22–)30–70(–90) cm; corollas light blue to violet, rarely light yellow or whitish, 14–20 mm; calyx lobe margins erose.||Penstemon attenuatus var. attenuatus|
|3||Stems (2–)5–40 cm; corollas bluish purple, 12–16 mm; calyx lobe margins erose or lacerate.||Penstemon attenuatus var. pseudoprocerus|