Penstemon thompsoniae

Stems prostrate or ascending, 4–15(–25) cm, retrorsely hairy, hairs appressed, white, scalelike. Leaves not leathery, densely retrorsely hairy, hairs appressed, white, scalelike; cauline 1–5 pairs, petiolate, 6–25(–33) × 2–6.5 mm, blade obovate to spatulate, base tapered, apex mucronate, sometimes rounded or obtuse. Thyrses continuous, secund, (1–)2–12 cm, axis retrorsely hairy, hairs appressed, white, scalelike, sometimes also glandular-pubescent distally, verticillasters (1–)3–12, cymes 1–3(–5)-flowered, 1 per node; proximal bracts spatulate to oblanceolate, 5–19 × 1.5–4 mm; peduncles and pedicels spreading to ascending, retrorsely hairy, hairs pointed, and, sometimes, sparsely glandular-pubescent. Flowers: calyx lobes lanceolate, 4–6 × 1–1.7 mm, herbaceous- or narrowly scarious-margined, sparsely glandular-pubescent and retrorsely hairy, hairs appressed, white, scalelike; corolla blue to violet or purple, lined internally abaxially with reddish violet nectar guides, ampliate, 10–18 mm, yellow-lanate internally abaxially, tube 6–7 mm, throat gradually inflated, 4.5–6 mm diam., 2-ridged abaxially; stamens reaching orifice or longer pair exserted, filaments glabrous, pollen sacs divergent, navicular, 0.8–1.2(–1.4) mm, sutures papillate; staminode 8–9 mm, exserted, flattened distally, 0.2–0.3 mm diam., tip recurved, distal 6–8 mm pubescent, hairs yellow or orange, to 0.8 mm; style 10–13 mm. Capsules 3.5–5.5 × 3–4 mm.

Phenology: Flowering May–Aug.
Habitat: Sandy to gravelly soils, sagebrush shrublands, pine-juniper woodlands, pine forests.
Elevation: 1500–3400 m.

Ariz., Calif., Nev., Utah.

Discussion

D. D. Keck (1937) recognized two subspecies in his treatment of Penstemon thompsoniae: subsp. jaegeri, restricted to mountains of Clark County, Nevada, which he distinguished by its few, remote stems and open inflorescences, and subsp. thompsoniae in Arizona, Nevada, and Utah, which he distinguished by its tufted stems and compact inflorescences. A morphologic continuum exists between the two subspecies.

Neese described var. desperatus from Beaver and Iron counties, Utah, and eastern Nevada, distinguishing it from var. thompsoniae by its longer stems and inflorescences, and smaller leaves. She later concluded that geographic variation in Penstemon thompsoniae was not sufficiently geographically correlated to recognize infraspecific taxa (E. C. Neese 1993).

Selected References

None.

Lower Taxa