Penstemon grandiflorus
Cat. Pl. Upper Louisiana, no. 64. 1813.
Stems erect, (40–)50–95(–120) cm, glabrous. Leaves basal and cauline, glabrous; basal and proximal cauline 30–160 × 6–50 mm, blade spatulate to obovate, base tapered, apex rounded to obtuse or acute; cauline 4–8 pairs, sessile, 18–90(–110) × 15–50 mm, blade spatulate to orbiculate, base clasping, apex rounded to obtuse. Thyrses interrupted, cylindric, 12–30(–40) cm, axis glabrous, verticillasters 3–7(–9), cymes 2–4-flowered; proximal bracts ovate to elliptic or orbiculate, (9–)16–83 × (9–)16–54 mm; peduncles and pedicels glabrous. Flowers: calyx lobes ovate to lanceolate, 7–11 × 2.5–4 mm, margins entire, rarely erose, herbaceous or narrowly scarious, glabrous; corolla lavender to blue or pinkish blue, with magenta nectar guides, ampliate, 35–48 mm, glabrous externally, glabrous internally, tube 10–13 mm, throat abruptly inflated, 15–18 mm diam., rounded abaxially; stamens included, pollen sacs opposite, 2.1–2.6 mm, sutures papillate; staminode 16–21 mm, included or reaching orifice, 2–2.6 mm diam., tip recurved to coiled, distal 1–2 mm sparsely villous, hairs golden yellow, to 0.5 mm; style 19–30 mm. Capsules 16–20(–25) × 8–15 mm. 2n = 16.
Phenology: Flowering Apr–Jul.
Habitat: Sandy or calcareous soils, tallgrass, mixed-grass, and sand prairies.
Elevation: 200–1800(–2400) m.
Distribution
Colo., Conn., Ill., Ind., Iowa, Kans., Mass., Mich., Minn., Mo., Mont., Nebr., N.Mex., N.Dak., Ohio, Okla., S.Dak., Tex., Wyo.
Discussion
Widely distributed in the western Midwest and Great Plains in the United States, Penstemon grandiflorus is cultivated as an ornamental for its showy flowers. Reports from Connecticut (D. W. Magee and H. E. Ahles 2007), Indiana (K. Yatskievych 2000), Massachusetts (Magee and Ahles), Michigan (E. G. Voss 1972–1996), and Ohio (T. S. Cooperrider 1995) appear to be based on introductions. Penstemon grandiflorus has been seeded along highways in Iowa and Nebraska, where it is also native.
The validity of the name Penstemon grandiflorus has been debated owing to the meager diagnosis by Nuttall. The name is accepted here, making P. bradburyi Pursh, an illegitimate, superfluous replacement for P. grandiflorus.
The Dakota, Kiowa, and Sioux tribes, centered in the Great Plains, use Penstemon grandiflorus as an analgesic, a gastrointestinal aid, and for fevers (D. E. Moerman 1998).
Selected References
None.