Penstemon pallidus |
Penstemon digitalis |
|
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eastern white beardtongue, pale beardtongue, pale penstemon |
foxglove beard-tongue, penstémon digitale, tall white beardtongue, talus slope penstemon |
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Habit | Herbs. | Herbs. |
Stems | ascending to erect, 25–55(–65) cm, retrorsely hairy and glandular-villous proximally, retrorsely hairy and glandular-pubescent distally, glandular hairs sometimes sparse, not glaucous. |
erect, 25–90 cm, glabrous or sparsely retrorsely hairy, slightly glaucous or not. |
Leaves | basal and cauline, basal often withering by anthesis, not leathery, sparsely to densely pubescent, sometimes also with scattered glandular hairs, abaxially, sparsely pubescent adaxially; basal and proximal cauline 20–120(–180) × 5–35(–40) mm, blade spatulate to obovate or ovate, base tapered, margins subentire or ± serrate or dentate, apex rounded to obtuse or acute; cauline 4–8 pairs, sessile, 22–100 × 4–24 mm, blade ovate to lanceolate, base truncate to clasping, margins subentire or ± serrate or dentate, apex acute to acuminate. |
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, 5–26(–30) cm, axis sparsely to densely glandular-pubescent, verticillasters 3–8, cymes 2–8(–16)-flowered, 2 per node; proximal bracts lanceolate, 7–72 × 2–22 mm, margins entire or ± dentate; peduncles and pedicels ascending, sparsely to densely glandular-pubescent. |
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 to lanceolate, (2–)3–5 × 1–3 mm, sparsely glandular-pubescent; corolla white, sometimes tinged lavender or blue, with reddish purple nectar guides, tubular to tubular-funnelform, 16–22 mm, glandular-pubescent externally, moderately whitish or yellowish lanate internally abaxially, tube 4–6 mm, throat slightly inflated, 4–7 mm diam., 2-ridged abaxially; stamens included, pollen sacs opposite, navicular, (0.8–)1–1.2 mm, dehiscing completely, connective splitting, sides glabrous, sutures papillate; staminode 10–12 mm, exserted, 0.2–0.3 mm diam., tip straight to slightly recurved, distal 8–9 mm moderately to densely villous, hairs yellow or golden yellow, to 1.5 mm; style 12–14 mm. |
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 | 5–7 × 3–5 mm, glabrous. |
8–14 × 4–6 mm, glabrous. |
2n | = 16. |
= 96. |
Penstemon pallidus |
Penstemon digitalis |
|
Phenology | Flowering Apr–Jun(–Jul). | Flowering Apr–Jul. |
Habitat | Tallgrass prairie, limestone and sandstone glades, barrens, rocky oak-hickory woodlands. | Prairies, meadows, roadsides, clearings in woods. |
Elevation | 10–300 m. (0–1000 ft.) | 10–500 m. (0–1600 ft.) |
Distribution |
AL; AR; CT; DC; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; NC; NH; NJ; NY; OH; PA; RI; TN; VA; VT; WI; WV; ON
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AL; AR; CT; DC; DE; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; NB; NS; ON; QC
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Discussion | Penstemon pallidus is concentrated in the Central Lowlands and Ozark Plateau of the central United States. F. W. Pennell (1935) believed it to be native there, having spread eastward as a result of human activities, as in Ontario. Penstemon brevisepalus, which has been synonymized with P. pallidus by many authors, is treated here as a distinct species. Characters distinguishing the species are discussed under 147. P. brevisepalus. Some specimens from north-central Arkansas and north-central Missouri are morphologically intermediate between Penstemon pallidus and P. arkansanus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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 (http://data.canadensys.net/vascan/taxon/7273). 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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 17, p. 214. | FNA vol. 17, p. 202. |
Parent taxa | Plantaginaceae > Penstemon > subg. Penstemon > sect. Penstemon | Plantaginaceae > Penstemon > subg. Penstemon > sect. Penstemon |
Sibling taxa | ||
Synonyms | P. alluviorum | |
Name authority | Small: Fl. S.E. U.S., 1060, 1337. (1903) — (as Pentstemon) | Nuttall ex Sims: Bot. Mag. 52: plate 2587. (1825) — (as Pentstemon) |
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