Man. S.E. Fl., 1204, 1508. 1933.
Herbs. Stems ascending to erect, 22–60 cm, retrorsely hairy and glandular-pubescent or glandular-villous, not glaucous. Leaves basal and cauline, basal sometimes withering by anthesis, not leathery, sparsely to densely pubescent, usually also sparsely glandular-hairy, abaxially, glabrous or sparsely pubescent adaxially; basal and proximal cauline 20–95 × 11–28 mm, blade spatulate to obovate or ovate, base tapered, margins subentire to ± serrate, apex rounded to obtuse; cauline 4 or 5, sessile or proximals short-petiolate, 35–95 × 11–32 mm, blade ovate to lanceolate or oblanceolate, base tapered to truncate or clasping, margins ± serrate or dentate, apex obtuse to acute. Thyrses interrupted, conic, (4–) 8–20 cm, axis sparsely to densely glandular-pubescent, verticillasters 3–8, cymes 5–16-flowered, 2 per node; proximal bracts lanceolate, 7–50 × 2–20 mm, margins entire or serrate; peduncles and pedicles spreading to ascending, sparsely to densely glandular-pubescent. Flowers: calyx lobes ovate, rarely lanceolate, (1.5–) 2–3.5 × 0.9–2.2 mm, sparsely glandular-pubescent; corolla lavender to purple, with reddish purple nectar guides, tubular to tubular-funnelform, 15–24 mm, glandular-pubescent externally, ± whitish lanate internally abaxially, tube 4–6 mm, throat slightly inflated, 4–7 mm diam., 2-ridged abaxially; stamens included, pollen-sacs opposite, navicular, 0.9–1.1 mm, dehiscing completely, connective splitting, sides glabrous, sutures papillate; staminode 12–18 mm, exserted, 0.3–0.5 mm diam., tip straight to slightly recurved, distal 8–9 mm ± villous, hairs yellow or golden yellow, to 1.5 mm; style 12–17 mm. Capsules 4–7 × 3–5 mm, glabrous.
Phenology: Flowering May–Jun.
Habitat: Rocky oak-hickory forests, bluffs, roadcuts.
Elevation: 200–700 m.
Ky., Tenn., Va., W.Va.
Penstemon brevisepalus has not been widely recognized in the literature or herbaria, usually being synonymized with P. canescens or P. pallidus. Penstemon brevisepalus combines features of P. canescens and P. pallidus, and its range lies between the ranges of those two species, with little overlap. In addition to calyx lobe length and corolla color, P. brevisepalus usually has more open inflorescences and cauline leaf margins that are more finely and regularly toothed compared to P. pallidus. Plants with pink- or lavender-tinged corollas occasionally occur in P. pallidus, and individuals with short calyx lobes (2–3 mm) also are encountered infrequently; they may be the sources of reports of P. brevisepalus elsewhere (for example, Georgia, Illinois, and Ohio).
"/4+timescorollathroat" is not declared as a valid unit of measurement for this property.