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Harbour's beardtongue

foxglove beard-tongue, penstémon digitale, tall white beardtongue, talus slope penstemon

Habit Herbs. Herbs.
Caudex

rhizomelike.

Stems

decumbent, ascending, or weakly erect, 4–18 cm, retrorsely hairy, not glaucous.

erect, 25–90 cm, glabrous or sparsely retrorsely hairy, slightly glaucous or not.

Leaves

cauline, not leathery, glabrate, retrorsely hairy, or puberulent;

cauline 2–4 pairs, petiolate or sessile, 7–28 × 3–12 mm, blade spatulate to oblanceolate, base tapered to clasping, margins entire, apex rounded or obtuse to acute.

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 or continuous, ± secund, 1–3 cm, axis ± glandular-pubescent, verticillasters 1 or 2(or 3), cymes 1- or 2-flowered, 1 or 2 per node;

proximal bracts lanceolate, 17–23 × 4–10 mm, margins entire;

peduncles and pedicels ascending to erect, retrorsely hairy and 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 lanceolate, 6–10 × 1.3–2 mm, glandular-pubescent;

corolla lavender or bluish lavender to lavender-purple, without nectar guides, bilabiate, not personate, tubular-funnelform, 15–20 mm, glandular-pubescent externally, densely white-lanate internally abaxially, tube 4–6 mm, throat gradually inflated, 5–6 mm diam., prominently 2-ridged abaxially;

stamens included, pollen sacs opposite, subexplanate, 0.7–0.9 mm, dehiscing completely, connective splitting, sides glabrous, sutures smooth;

staminode 8–9 mm, included, 0.3–0.4 mm diam., tip recurved, distal 4–5 mm moderately to densely lanate, hairs yellow, to 1 mm;

style 11–12 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

6–8 × 4–5 mm, glabrous.

8–14 × 4–6 mm, glabrous.

2n

= 16.

= 96.

Penstemon harbourii

Penstemon digitalis

Phenology Flowering Jun–Aug. Flowering Apr–Jul.
Habitat Alpine talus, gravel slopes, boulder fields. Prairies, meadows, roadsides, clearings in woods.
Elevation 3200–4200 m. (10500–13800 ft.) 10–500 m. (0–1600 ft.)
Distribution
from FNA
CO
[WildflowerSearch map]
[BONAP county map]
from FNA
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
[WildflowerSearch map]
[BONAP county map]
Discussion

Penstemon harbourii is found on the high peaks of the Central Rocky Mountains. Populations have been documented in at least 17 counties. Habit, pubescence, and root characters of P. harbourii are somewhat anomalous in sect. Penstemon, prompting D. D. Keck (1945) to suggest possible ties with sect. Caespitosi or sect. Cristati. Molecular data appear to provide support for ties with sect. Caespitosi (A. D. Wolfe et al. 2006; C. A. Wessinger et al. 2016).

(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. 206. FNA vol. 17, p. 202.
Parent taxa Plantaginaceae > Penstemon > subg. Penstemon > sect. Penstemon Plantaginaceae > Penstemon > subg. Penstemon > sect. Penstemon
Sibling taxa
P. abietinus, P. absarokensis, P. acaulis, P. acuminatus, P. alamosensis, P. albertinus, P. albidus, P. albomarginatus, P. ambiguus, P. ammophilus, P. anguineus, P. angustifolius, P. arenarius, P. arenicola, P. aridus, P. arkansanus, P. attenuatus, P. atwoodii, P. auriberbis, P. australis, P. azureus, P. baccharifolius, P. barbatus, P. barnebyi, P. barrettiae, P. bicolor, P. bleaklyi, P. bracteatus, P. breviculus, P. brevisepalus, P. buckleyi, P. caesius, P. caespitosus, P. calcareus, P. californicus, P. calycosus, P. canescens, P. cardinalis, P. cardwellii, P. carnosus, P. caryi, P. centranthifolius, P. cinicola, P. clevelandii, P. clutei, P. cobaea, P. comarrhenus, P. compactus, P. concinnus, P. confertus, P. confusus, P. crandallii, P. cusickii, P. cyananthus, P. cyaneus, P. cyanocaulis, P. cyathophorus, P. dasyphyllus, P. davidsonii, P. deamii, P. deaveri, P. debilis, P. degeneri, P. deustus, P. digitalis, P. diphyllus, P. discolor, P. dissectus, P. distans, P. dolius, P. duchesnensis, P. eatonii, P. elegantulus, P. ellipticus, P. eriantherus, P. euglaucus, P. fendleri, P. filiformis, P. flavescens, P. floribundus, P. floridus, P. flowersii, P. franklinii, P. fremontii, P. fruticiformis, P. fruticosus, P. gairdneri, P. gibbensii, P. glaber, P. glandulosus, P. glaucinus, P. globosus, P. goodrichii, P. gormanii, P. gracilentus, P. gracilis, P. grahamii, P. grandiflorus, P. griffinii, P. grinnellii, P. guadalupensis, P. hallii, P. harringtonii, P. havardii, P. haydenii, P. heterodoxus, P. heterophyllus, P. hirsutus, P. humilis, P. idahoensis, P. immanifestus, P. incertus, P. inflatus, P. jamesii, P. janishiae, P. kingii, P. kralii, P. labrosus, P. laetus, P. laevigatus, P. laevis, P. lanceolatus, P. laricifolius, P. laxiflorus, P. laxus, P. leiophyllus, P. lemhiensis, P. lentus, P. leonardii, P. linarioides, P. longiflorus, P. lyallii, P. marcusii, P. mensarum, P. metcalfei, P. miser, P. moffatii, P. monoensis, P. montanus, P. moriahensis, P. mucronatus, P. multiflorus, P. murrayanus, P. nanus, P. navajoa, P. neomexicanus, P. neotericus, P. newberryi, P. nitidus, P. nudiflorus, P. oklahomensis, P. oliganthus, P. ophianthus, P. osterhoutii, P. ovatus, P. pachyphyllus, P. pahutensis, P. pallidus, P. palmeri, P. papillatus, P. parryi, P. parvulus, P. parvus, P. patens, P. payettensis, P. paysoniorum, P. peckii, P. penlandii, P. pennellianus, P. perpulcher, P. personatus, P. petiolatus, P. pinifolius, P. pinorum, P. platyphyllus, P. pratensis, P. procerus, P. pruinosus, P. pseudoputus, P. pseudospectabilis, P. pudicus, P. pumilus, P. purpusii, P. putus, P. radicosus, P. rattanii, P. retrorsus, P. rhizomatosus, P. richardsonii, P. roezlii, P. rostriflorus, P. rubicundus, P. rupicola, P. rydbergii, P. saxosorum, P. scapoides, P. scariosus, P. secundiflorus, P. seorsus, P. sepalulus, P. serrulatus, P. smallii, P. spatulatus, P. speciosus, P. spectabilis, P. stenophyllus, P. stephensii, P. strictiformis, P. strictus, P. subglaber, P. subserratus, P. subulatus, P. sudans, P. superbus, P. tenuiflorus, P. tenuis, P. teucrioides, P. thompsoniae, P. thurberi, P. tidestromii, P. tiehmii, P. tracyi, P. triflorus, P. triphyllus, P. tubaeflorus, P. uintahensis, P. utahensis, P. venustus, P. virens, P. virgatus, P. wardii, P. washingtonensis, P. watsonii, P. whippleanus, P. wilcoxii, P. wrightii, P. xylus, P. yampaënsis
P. abietinus, P. absarokensis, P. acaulis, P. acuminatus, P. alamosensis, P. albertinus, P. albidus, P. albomarginatus, P. ambiguus, P. ammophilus, P. anguineus, P. angustifolius, P. arenarius, P. arenicola, P. aridus, P. arkansanus, P. attenuatus, P. atwoodii, P. auriberbis, P. australis, P. azureus, P. baccharifolius, P. barbatus, P. barnebyi, P. barrettiae, P. bicolor, P. bleaklyi, P. bracteatus, P. breviculus, P. brevisepalus, P. buckleyi, P. caesius, P. caespitosus, P. calcareus, P. californicus, P. calycosus, P. canescens, P. cardinalis, P. cardwellii, P. carnosus, P. caryi, P. centranthifolius, P. cinicola, P. clevelandii, P. clutei, P. cobaea, P. comarrhenus, P. compactus, P. concinnus, P. confertus, P. confusus, P. crandallii, P. cusickii, P. cyananthus, P. cyaneus, P. cyanocaulis, P. cyathophorus, P. dasyphyllus, P. davidsonii, P. deamii, P. deaveri, P. debilis, P. degeneri, P. deustus, P. diphyllus, P. discolor, P. dissectus, P. distans, P. dolius, P. duchesnensis, P. eatonii, P. elegantulus, P. ellipticus, P. eriantherus, P. euglaucus, P. fendleri, P. filiformis, P. flavescens, P. floribundus, P. floridus, P. flowersii, P. franklinii, P. fremontii, P. fruticiformis, P. fruticosus, P. gairdneri, P. gibbensii, P. glaber, P. glandulosus, P. glaucinus, P. globosus, P. goodrichii, P. gormanii, P. gracilentus, P. gracilis, P. grahamii, P. grandiflorus, P. griffinii, P. grinnellii, P. guadalupensis, P. hallii, P. harbourii, P. harringtonii, P. havardii, P. haydenii, P. heterodoxus, P. heterophyllus, P. hirsutus, P. humilis, P. idahoensis, P. immanifestus, P. incertus, P. inflatus, P. jamesii, P. janishiae, P. kingii, P. kralii, P. labrosus, P. laetus, P. laevigatus, P. laevis, P. lanceolatus, P. laricifolius, P. laxiflorus, P. laxus, P. leiophyllus, P. lemhiensis, P. lentus, P. leonardii, P. linarioides, P. longiflorus, P. lyallii, P. marcusii, P. mensarum, P. metcalfei, P. miser, P. moffatii, P. monoensis, P. montanus, P. moriahensis, P. mucronatus, P. multiflorus, P. murrayanus, P. nanus, P. navajoa, P. neomexicanus, P. neotericus, P. newberryi, P. nitidus, P. nudiflorus, P. oklahomensis, P. oliganthus, P. ophianthus, P. osterhoutii, P. ovatus, P. pachyphyllus, P. pahutensis, P. pallidus, P. palmeri, P. papillatus, P. parryi, P. parvulus, P. parvus, P. patens, P. payettensis, P. paysoniorum, P. peckii, P. penlandii, P. pennellianus, P. perpulcher, P. personatus, P. petiolatus, P. pinifolius, P. pinorum, P. platyphyllus, P. pratensis, P. procerus, P. pruinosus, P. pseudoputus, P. pseudospectabilis, P. pudicus, P. pumilus, P. purpusii, P. putus, P. radicosus, P. rattanii, P. retrorsus, P. rhizomatosus, P. richardsonii, P. roezlii, P. rostriflorus, P. rubicundus, P. rupicola, P. rydbergii, P. saxosorum, P. scapoides, P. scariosus, P. secundiflorus, P. seorsus, P. sepalulus, P. serrulatus, P. smallii, P. spatulatus, P. speciosus, P. spectabilis, P. stenophyllus, P. stephensii, P. strictiformis, P. strictus, P. subglaber, P. subserratus, P. subulatus, P. sudans, P. superbus, P. tenuiflorus, P. tenuis, P. teucrioides, P. thompsoniae, P. thurberi, P. tidestromii, P. tiehmii, P. tracyi, P. triflorus, P. triphyllus, P. tubaeflorus, P. uintahensis, P. utahensis, P. venustus, P. virens, P. virgatus, P. wardii, P. washingtonensis, P. watsonii, P. whippleanus, P. wilcoxii, P. wrightii, P. xylus, P. yampaënsis
Synonyms P. alluviorum
Name authority A. Gray: Proc. Amer. Acad. Arts 6: 71. (1862) — (as Pentstemon) Nuttall ex Sims: Bot. Mag. 52: plate 2587. (1825) — (as Pentstemon)
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