Penstemon strictiformis

Stems ascending to erect, (11–)16–55(–70) cm, glabrous, not glaucous. Leaves basal and cauline, ± leathery or not, glabrous, not glaucous; basal and proximal cauline 60–90(–150) × 5–12 mm, blade oblanceolate to lanceolate, base tapered, margins entire, apex acute; cauline 3–5 pairs, sessile, 18–80 × 3–18 mm, blade lanceolate, base tapered to truncate or clasping, apex acute. Thyrses continuous or interrupted, ± secund, 5–40 cm, axis glabrous, verticillasters 4–8(–12), cymes 2- or 3(–5)-flowered, 2 per node; proximal bracts lanceolate, 12–46(–115) × 2–15 mm, apex acuminate; peduncles and pedicels glabrous or ± glandular, peduncles to 20 mm, pedicels 2–13(–18) mm. Flowers: calyx lobes ovate to lanceolate, (4.5–)6–8(–9) × 2–3 mm, apex acuminate to caudate, glabrous or ± glandular proximally; corolla lavender to blue, without nectar guides, ventricose, (19–)25–32 mm, glabrous externally, glabrous internally, tube 5–7 mm, throat gradually to abruptly inflated, not constricted at orifice, 7–10 mm diam., slightly 2-ridged abaxially; stamens: longer pair slightly exserted, pollen sacs divergent, navicular-sigmoid, 1.3–2.3 mm, dehiscing incompletely, proximal 1/5–1/4 indehiscent, connective not splitting, sides sparsely to densely lanate, hairs white, to 1 mm, sutures denticulate, teeth to 0.1 mm; staminode (8–)11–15 mm, included, 0.5–0.1(–1.2) mm diam., tip straight to recurved, distal (2–)4–5 mm sparsely to moderately villous, hairs yellow or white, to 1 mm; style (11–)13–21 mm. Capsules 7–11 × 4–6 mm.

Phenology: Flowering May–Jun.
Habitat: Juniper and pinyon-juniper woodlands.
Elevation: 1700–2400 m.

Ariz., Colo., N.Mex., Utah.

Discussion

Plants of Penstemon strictiformis from southwestern Colorado (Montezuma County) and northwestern New Mexico (San Juan County) closely match the type, with large corollas, broad calyx lobes, and large pollen sacs. Plants from southeastern Utah have relatively smaller corollas, narrower calyx lobes, and smaller pollen sacs.

Penstemon strictiformis often is confused with P. strictus; many specimens from southwestern Colorado are difficult to place with certainty due to morphologic intermediacy.

Selected References

None.

Lower Taxa