Proc. Amer. Acad. Arts 11: 94. 1876
Herbs. Stems ascending to erect, 30–70 cm, glaucous. Leaves: basal and proximal cauline 15–90 × 8–35 mm, blade ovate, base truncate to tapered, margins entire or coarsely dentate, apex acute; cauline 4–7 pairs, short-petiolate or sessile, 10–70 × 8–32 mm, blade cordate to triangular-lanceolate, base tapered or truncate on proximal leaves to connate-perfoliate on distal leaves, margins coarsely dentate, sometimes entire, apex acute. Thyrses interrupted, secund, 10–40(–65) cm, axis glabrous or glandular-pubescent, verticillasters 6–12(–22), cymes 2–8-flowered; proximal bracts depressed-ovate to ovate or triangular, 6–45 × 11–26 mm; peduncles and pedicels spreading to ascending or erect, glabrous or glandular-pubescent. Flowers: calyx lobes ovate, 3.2–6 × 1.6–4 mm, glabrous or glandular-pubescent; corolla red to reddish purple, with or without reddish or reddish purple nectar guides, bilabiate, tubular-funnelform to slightly ventricose, 17–24 mm, glandular-pubescent externally, glabrous internally or glandular-pubescent, sometimes also pilose abaxially, tube 6–9 mm, length 1.8–2 times calyx lobes, throat gradually inflated, slightly constricted or not at orifice, 5–8 mm diam., rounded abaxially; stamens included or longer pair reaching orifice, filaments glabrous, pollen sacs navicular or explanate, 1.2–1.7 mm, sutures smooth or denticulate, teeth to 0.1 mm; staminode 6–11 mm, included, 0.3–0.5 mm diam., tip straight to recurved, glabrous or distal 1–6 mm pilose, hairs yellow, to 0.8 mm, proximal 1–2 mm sometimes glandular-puberulent; style 11–14 mm, glabrous. Capsules 6–9 × 5–7 mm, glabrous. 2n = 16.
Calif., nw Mexico.
Varieties 3 (3 in the flora).
Penstemon clevelandii is an ancient, stable, diploid hybrid between P. centranthifolius and P. spectabilis (A. D. Wolfe et al. 1998). Penstemon ×parishii A. Gray is a naturally occurring hybrid, also with P. centranthifolius and P. spectabilis as parents; it has been reported from Los Angeles, Riverside, San Bernardino, and San Diego counties, California (D. D. Keck 1937b; Paul Wilson and M. Valenzuela 2002). Keck reported that P. clevelandii var. clevelandii could be distinguished from P. ×parishii by the former’s shorter and narrower corollas, more glandular-pubescent inflorescences, and explanate pollen sacs.
|1||Distal cauline leaves sessile, bases connate-perfoliate; pollen sacs navicular, sutures denticulate; peduncles, pedicels, and calyx lobes glabrous.||Penstemon clevelandii var. connatus|
|1||Distal cauline leaves short-petiolate or sessile, bases tapered or truncate; pollen sacs explanate, sutures smooth; peduncles, pedicels, and calyx lobes glandular-pubescent, rarely glabrous.||> 2|
|2||Corollas glandular-pubescent internally, not pilose or sparsely white- or yellowish pilose internally abaxially; staminodes 9–11 mm.||Penstemon clevelandii var. clevelandii|
|2||Corollas not glandular-pubescent internally, densely white- or yellowish pilose internally abaxially; staminodes 6–8 mm.||Penstemon clevelandii var. mohavensis|