Penstemon digitalis

Nuttall ex Sims

Bot. Mag. 52: plate 2587. 1825. (as Pentstemon)

Common names: Tall white beardtongue penstémon digitale
Synonyms: Penstemon alluviorum Pennell
Treatment appears in FNA Volume 17. Treatment on page 202. Mentioned on page 185, 197, 199, 211, 225.

Herbs. Stems erect, 25–90 cm, glabrous or sparsely retrorsely hairy, slightly glaucous or not. Leaves basal and cauline, basal sometimes withering by anthesis, not leathery, glabrous; basal and proximal cauline 30–180(–250) × 4–38(–70) mm, blade spatulate to obovate or lanceolate, base tapered, margins entire or ± serrate or denticulate, apex rounded to obtuse or acute; cauline 5–8 pairs, petiolate or sessile, 26–195 × 4–55 mm, blade ovate to lanceolate, base tapered to clasping, margins entire or denticulate, apex acuminate to acute. Thyrses interrupted, conic, 7–26(–34) cm, axis glabrous proximally, sparsely to densely glandular-pubescent distally, verticillasters (2 or)3–6, cymes (3–)5–12(–18)-flowered, 2 per node; proximal bracts lanceolate to linear, 9–105 × 1–40 mm, margins entire, sometimes serrulate; peduncles and pedicels spreading to ascending, sparsely glandular-pubescent. Flowers: calyx lobes ovate, sometimes lanceolate, 4–8 × 2–3 mm, apex acute to acuminate, glandular-pubescent; corolla white, sometimes tinged lavender, with reddish purple nectar guides, ventricose, (17–)20–30 mm, glandular-pubescent externally, sparsely to moderately white-pubescent internally abaxially, tube 6–9 mm, throat abruptly inflated, 8–12 mm diam., slightly 2-ridged abaxially; stamens included or longer pair reaching orifice, pollen sacs opposite, navicular, 1.4–1.7 mm, dehiscing completely, connective splitting, sides sparsely pubescent, hairs white or purplish, to 0.6 mm, rarely glabrous, sutures papillate; staminode 13–17 mm, reaching orifice, 0.3–0.4 mm diam., tip straight to slightly recurved, distal 6–8 mm sparsely to moderately villous, hairs yellowish, to 1.5(–2) mm; style 13–18 mm. Capsules 8–14 × 4–6 mm, glabrous. 2n = 96.

Phenology: Flowering Apr–Jul.
Habitat: Prairies, meadows, roadsides, clearings in woods.
Elevation: 10–500 m.


N.B., N.S., Ont., Que., Ala., Ark., Conn., Del., D.C., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Tex., Vt., Va., W.Va., Wis.


Penstemon digitalis appears to be native in the central Mississippi River Basin, with human activities expanding its range, particularly eastward (F. W. Pennell 1935). It is listed in VASCAN as introduced in the four Canadian provinces where it occurs (

Plants resembling Penstemon digitalis but with smaller corollas (17–23 mm versus 23–30 mm), less glandular-pubescent inflorescences, less scarious-margined calyx lobes, and stems sometimes puberulent (versus glabrous) have been named P. alluviorum. Plants with those features come mostly from the southeastern Central Lowlands and north-central Coastal Plain provinces in the eastern United States in the south-central part of the range of P. digitalis (Alabama, Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri, Ohio, and Tennessee). A. C. Koelling (1964) observed overlap in characters used to distinguish P. alluviorum from P. digitalis and concluded it was a small-flowered variant of P. digitalis.

Specimens of Penstemon digitalis with lanceolate and acuminate-tipped calyx lobes can be mistaken for P. calycosus, but calyx lobe length and, usually, the presence of hairs on the pollen sacs allow them to be accurately identified.

Penstemon digitalis is widely cultivated and spreads readily. R. R. Clinebell and P. Bernhardt (1998) found evidence that plants are self-compatible.

Selected References


Lower Taxa

... more about "Penstemon digitalis"
Craig C. Freeman +
Nuttall ex Sims +
Tall white beardtongue +  and penstémon digitale +
N.B. +, N.S. +, Ont. +, Que. +, Ala. +, Ark. +, Conn. +, Del. +, D.C. +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Nebr. +, N.H. +, N.J. +, N.Y. +, N.C. +, Ohio +, Okla. +, Pa. +, R.I. +, S.C. +, S.Dak. +, Tenn. +, Tex. +, Vt. +, Va. +, W.Va. +  and Wis. +
10–500 m. +
Prairies, meadows, roadsides, clearings in woods. +
Flowering Apr–Jul. +
Penstemon alluviorum +
Penstemon digitalis +
Penstemon sect. Penstemon +
species +