Penstemon angustifolius

Stems ascending to erect, (6–)15–45(–65) cm, glabrous or scabrous. Leaves basal and cauline, basal not reduced, glabrous, sometimes scabrous; basal and proximal cauline (25–)40–90 × 2–18 mm, blade spatulate to oblanceolate or linear, base tapered, apex rounded to obtuse or acute; cauline 2–8 pairs, sessile, 18–113 × 2–24(–40) mm, blade ovate to lanceolate or linear, base tapered to cordate-clasping, apex acute to acuminate. Thyrses continuous or interrupted, cylindric, (2–)5–30(–37) cm, axis glabrous, rarely scabrous, verticillasters (3–)5–15(–26), cymes (2–)4–8(–10)-flowered; proximal bracts ovate to lanceolate or linear, (3–)12–98 × (1–)2–28 mm; peduncles and pedicels glabrous or scabrous, peduncles to 3 mm. Flowers: calyx lobes ovate to lanceolate, 4–8 × 1–2.5 mm, margins entire or erose, broadly scarious, glabrous or scabrous; corolla lavender, blue, or pink, with violet or reddish purple nectar guides, tubular-funnelform, 13–20(–22) mm, glabrous externally, sparsely white-pubescent internally abaxially or glabrous, tube 6–8 mm, throat gradually inflated, 4–6 mm diam., rounded abaxially; stamens included or longer pair reaching orifice, pollen sacs opposite, (0.9–)1.1–1.5 mm, sutures papillate; staminode 8–10 mm, reaching orifice, 0.9–1.2 mm diam., tip recurved, distal 4–6 mm sparsely villous, hairs golden yellow, to 1 mm, hairs on proximal part of staminode mostly along margins; style 8–12 mm. Capsules 9–15 × 5–7 mm.

Distribution

w United States.

Discussion

Varieties 5 (5 in the flora).

Penstemon angustifolius comprises five varieties: two widespread in the west-central Great Plains and three with more limited, allopatric ranges.

Selected References

None.

Lower Taxa

Penstemon angustifolius var. angustifolius, Penstemon angustifolius var. caudatus, Penstemon angustifolius var. dulcis, Penstemon angustifolius var. venosus, Penstemon angustifolius var. vernalensis

Key

1	Corollas pink; cauline leaf blades lanceolate to linear; Juab and Millard counties, Utah.	Penstemon angustifolius var. dulcis
1	Corollas blue or lavender, rarely pink; cauline leaf blades ovate to lanceolate or linear (if corollas pink, leaf blades broader or plants not of Juab or Millard counties, Utah); Arizona, Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Utah, Wyoming.	> 2
2	Cauline leaf blades and proximal bracts lanceolate to linear.	> 3
3	Stems glabrous or scabrous; corollas 14–18 mm; cauline leaves 2–5(or 6) pairs; stems (6–)10–30 cm; Colorado, Montana, Nebraska, North Dakota, South Dakota, Wyoming.	Penstemon angustifolius var. angustifolius
3	Stems glabrous, rarely scabrous; corollas (14–)18–20(–22) mm; cauline leaves 4–7 pairs; stems (8–)15–45 cm; Colorado, Utah.	Penstemon angustifolius var. vernalensis
2	Cauline leaf blades and proximal bracts ovate to lanceolate.	> 4
4	Corollas 13–20(–22) mm, blue, rarely lavender or pink; Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Wyoming.	Penstemon angustifolius var. caudatus
4	Corollas 14–17 mm, blue to lavender or pink; Arizona, Colorado, New Mexico, Utah.	Penstemon angustifolius var. venosus