Penstemon saxosorum

Stems erect, (10–)30–80 cm, glabrous, not glaucous. Leaves basal and cauline, not leathery, glabrous, not glaucous; basal and proximal cauline 26–140 × 3–19 mm, blade oblanceolate, base tapered, margins entire, apex obtuse to acute; cauline 2–5 pairs, sessile, 50–90 × (3–)6–9(–18) mm, blade oblanceolate to lanceolate, base clasping, apex acute. Thyrses continuous to ± interrupted, secund or cylindric, 5–40 cm, axis glabrous or ± glandular-pubescent, verticillasters (4 or)5–9, cymes 1–5-flowered, 2 per node; proximal bracts lanceolate, 15–54 × 2–15 mm; peduncles and pedicels glabrous or glandular-pubescent, peduncles to 11 mm, pedicels 1–10 mm. Flowers: calyx lobes ovate, 3.5–8 × 1.8–3 mm, margins erose, glabrous or glandular-pubescent; corolla blue to bluish violet, with or without reddish purple nectar guides, ventricose, 17–25(–30) mm, glabrous or glandular-pubescent externally, glabrous or ± glandular-pubescent internally abaxially, tube 5–8 mm, throat gradually inflated, slightly constricted at orifice, 6–8 mm diam., rounded abaxially; stamens: longer pair reaching orifice or slightly exserted, pollen sacs opposite, navicular, 1.2–1.8 mm, dehiscing incompletely, connective not splitting, sides sparsely to moderately hispid or pubescent, hairs whitish, to 0.3 mm, sutures denticulate, teeth to 0.1 mm; staminode 12–15 mm, reaching orifice or slightly exserted, 0.4–0.6 mm diam., tip straight to recurved, distal 3–5 mm sparsely villous, hairs yellow, to 1 mm; style 15–18 mm. Capsules 8–12 × 4–6 mm. 2n = 16.

Phenology: Flowering Jun–Aug.
Habitat: Sagebrush shrublands, openings in pine forests.
Elevation: 2400–3600 m.

Colo., Wyo.

Discussion

Penstemon saxosorum is known in north-central and northwestern Colorado and south-central Wyoming. Populations in the Bridger Basin in Moffat County, Colorado, and Daggett and Uintah counties, Utah, lie between the main ranges of P. saxosorum and P. subglaber. Plants in those populations have pollen sacs 0.7–0.9 mm; corollas sparsely glandular and 18–20 mm; and corolla throats 5–7 mm in diameter. M. L. Moorman (1982) believed that they represented an undescribed species. Pending further study, Colorado plants are referred to P. saxosorum and Utah plants to P. subglaber.

Selected References

None.

Lower Taxa