Penstemon acuminatus
Penstemon sect. Coerulei
sand dune penstemon, sand-dune beardtongue, sharp-leaf penstemon
ascending to erect, (9–)20–60 cm, glabrous or ± scabrous, especially distally.
glabrous, sometimes scabrous, glaucous.
basal and cauline, glabrous, sometimes scabrous;
basal and proximal cauline (14–)30–95 × 4–15(–24) mm, blade oblanceolate to elliptic, base tapered, apex obtuse to acute or mucronate;
cauline (2 or)3–6(or 7) pairs, sessile, 18–60(–85) × (4–)8–28 mm, blade ovate to lanceolate, base tapered to cordate-clasping, apex acute to acuminate.
basal and cauline, sometimes basal absent or reduced, opposite, leathery, glabrous, rarely scabrous, glaucous;
basal and proximal cauline petiolate, sometimes short-petiolate (P. immanifestus, P. lentus);
cauline sessile, sometimes short-petiolate, blade obovate, ovate, spatulate, trullate, oblanceolate, lanceolate, oblong, elliptic, linear, or orbiculate, margins entire.
continuous or interrupted, cylindric, 6–25(–30) cm, axis glabrous, rarely scabrous or glutinous, verticillasters (5–)7–15, cymes (2–)4–8(–12)-flowered;
proximal bracts ovate to lanceolate, 14–60 × 9–30 mm, margins entire, apex obtuse to acuminate or caudate;
peduncles and pedicels glabrous or scabrous, sometimes also glutinous, peduncles to 4 mm.
continuous or interrupted, cylindric, sometimes secund, axis glabrous, rarely scabrous or glutinous, cymes 2 per node;
peduncles and pedicels ascending to erect.
calyx lobes lanceolate, (3.2–)4.5–10 × 1.2–3.2(–3.8) mm, margins entire or erose, herbaceous or narrowly scarious, glabrous or scabrous proximally and, sometimes, along margins, sometimes also glutinous;
corolla blue to violet or purple, with reddish purple nectar guides, tubular-funnelform, 11–20 mm, glabrous externally, glabrous internally, tube 5–9 mm, throat gradually inflated, 4–6 mm diam., rounded abaxially;
stamens included or longer pair reaching orifice to slightly exserted, pollen sacs opposite, navicular, 0.7–1.3(–1.5) mm, sutures papillate;
staminode 6–12 mm, reaching orifice, 0.6–1 mm diam., tip recurved, distal 1.5–3.5 mm densely pilose, hairs golden yellow, to 0.6 mm, hairs on proximal part of staminode mostly along margins;
style 8–15 mm.
calyx lobes: margins entire or erose, herbaceous or ± scarious, glabrous, rarely scabrous, glandular, glandular-pubescent, or glutinous;
corolla lavender to blue, violet, purple, or pink, rarely white or red, bilaterally symmetric, rarely nearly radially symmetric (P. cyathophorus), weakly, rarely strongly, bilabiate, not personate, tubular-funnelform, funnelform, or weakly ventricose, rarely tubular-salverform or weakly ampliate, glabrous externally, rarely obscurely glandular, glabrous or hairy internally abaxially, throat slightly to abruptly inflated, not constricted at orifice, rounded abaxially, rarely slightly 2-ridged;
stamens included to exserted, filaments glabrous, pollen sacs opposite, rarely divergent or parallel, navicular, rarely explanate (P. murrayanus), dehiscing completely, connective splitting, sides glabrous, sutures papillate, sometimes smooth;
staminode included to exserted, flattened distally, (0.2–)0.4–3 mm diam., tip recurved, rarely coiled or straight, distal 10–50(–70)% hairy, hairs to 2.5 mm, rarely glabrous;
style glabrous.
7–13 × 4–7 mm.
glabrous.
brown or dark brown, angled, angled-elongate, or disciform, 1.8–5.4 mm.
Penstemon acuminatus
Penstemon sect. Coerulei
Varieties 2 (2 in the flora).
Penstemon acuminatus includes the northern var. acuminatus, which has denser thyrses than the southern var. latebracteatus. Herbage of var. acuminatus is usually scabrous; herbage of var. latebracteatus is rarely scabrous.
The Blackfoot tribe of the Central Rocky Mountains use Penstemon acuminatus as an analgesic, antiemetic, and gastrointestinal aid (D. E. Moerman 1998).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 20 (20 in the flora).
D. D. Keck (1951) proposed the section name Anularius for sect. Coerulei, believing that the name of Pennell was invalid. N. H. Holmgren (1979b) concluded that the section names of Pennell are valid and that sect. Anularius Keck is invalid; the new combinations by Keck in that publication lacked descriptions.
Members of sect. Coerulei usually are recognized by their mostly glabrous, glaucous, and fleshy herbage, their blue or pink corollas that are glabrous, rarely obscurely glandular, externally, and their relatively broad and heavily bearded staminodes. Penstemon murrayanus has red corollas and glabrous staminodes. Members of sect. Coerulei mostly occur on well-drained, sandy soils. Molecular data (C. A. Wessinger et al. 2016) support the monophyly of the section.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Styles 11–15 mm; corollas 14–20 mm; pollen sacs 0.8–1.3(–1.5) mm; calyx lobes 5–10 mm. | var. acuminatus |
1. Styles 8–11 mm; corollas 11–15 mm; pollen sacs 0.7–1 mm; calyx lobes (3.2–)4.5–7 mm. | var. latebracteatus |
1. Corollas red; staminodes glabrous; pollen sacs explanate. | P. murrayanus |
1. Corollas lavender to blue, violet, purple, or pink, rarely white; staminodes hairy; pollen sacs navicular. | → 2 |
2. Pollen sacs parallel or divergent; stamens: 2 or 4 prominently exserted; corollas without nectar guides. | → 3 |
3. Stamens: 4 exserted; pollen sacs 1.2–1.5 mm; corollas 11–14 mm. | P. cyathophorus |
3. Stamens: 2 exserted; pollen sacs 2–3 mm; corollas 17–24 mm. | P. harringtonii |
2. Pollen sacs opposite or divergent; stamens included or longer pair reaching orifice to slightly exserted; corollas usually with nectar guides. | → 4 |
4. Corollas 21–48 mm, ampliate, glabrous internally, throats abruptly inflated. | → 5 |
5. Corollas 35–48 mm; cauline leaf blades spatulate to orbiculate. | P. grandiflorus |
5. Corollas 21–28 mm; cauline leaf blades lanceolate to linear. | P. haydenii |
4. Corollas 10–25(–28) mm, tubular-funnelform, tubular-salverform, funnelform, or ventricose, white-villous internally abaxially or glabrous, throats not abruptly inflated. | → 6 |
6. Corollas tubular-salverform; thyrses interrupted. | P. fendleri |
6. Corollas tubular-funnelform, funnelform, or ventricose; thyrses continuous or interrupted. | → 7 |
7. Stems 3–10(–15) cm; cauline leaf pairs 1–3; thyrses 1–6 cm; verticillasters 1–5(or 6). | P. bracteatus |
7. Stems (4–)7–77(–82) cm; cauline leaf pairs 1–8(or 9); thyrses (2–)3–37(–57) cm; verticillasters (2 or)3–20(–35). | → 8 |
8. Thyrses secund. | → 9 |
9. Cauline leaves 2–4 pairs; staminodes 8–9 mm, distal 3–4 mm sparsely to densely villous, hairs yellowish, to 1 mm; Arizona, Colorado, New Mexico, Utah. | P. lentus |
9. Cauline leaves 4–6 pairs; staminodes 10–13 mm, distal 4–6 mm densely villous, hairs golden yellow, to 2 mm; Colorado, New Mexico, Wyoming. | P. secundiflorus |
8. Thyrses cylindric. | → 10 |
10. Staminodes 2–3 mm diam.; corollas with nectar guides, sparsely to moderately white-villous internally abaxially, rarely glabrous. | P. osterhoutii |
10. Staminodes (0.2–)0.4–2 mm diam.; corollas with or without nectar guides, glabrous or sparsely white-villous internally abaxially. | → 11 |
11. Corollas pink or white. | → 12 |
12. Corollas white. | P. lentus |
12. Corollas pink. | → 13 |
13. Leaves: basal usually reduced or absent; corollas glabrous internally; staminodes: distal 0.5–1.5 mm lanulose, hairs to 0.6 mm. | P. flowersii |
13. Leaves: basal not reduced; corollas sparsely white-hairy internally abaxially or glabrous; staminodes: distal 2–6 mm villous, hairs to 1 mm. | → 14 |
14. Cauline leaf apices acute to acuminate; corollas tubular-funnelform; calyx lobes ovate to lanceolate, 4–8 × 1–2.5 mm. | P. angustifolius |
14. Cauline leaf apices obtuse to acute; corollas funnelform to ventricose; calyx lobes ovate, 5–8(–12) × 2–3.5 mm. | P. immanifestus |
11. Corollas blue, pinkish blue, lavender-blue, lavender, violet, or purple, rarely some individuals with corollas pink. | → 15 |
15. Cauline leaf blades ovate to orbiculate; corollas with nectar guides, villous internally abaxially. | P. mucronatus |
15. Cauline leaf blades elliptic to ovate, obovate, lanceolate, oblanceolate, or linear; corollas with or without nectar guides, glabrous or villous internally abaxially. | → 16 |
16. Stems decumbent to ascending, (4–)7–18(–30) cm; thyrses continuous; proximal bracts oblanceolate to lanceolate; corollas (10–)12–15 mm; pollen sacs 0.7–0.8 mm. | P. arenicola |
16. Stems ascending to erect, (5–)9–60(–82) cm; thyrses interrupted or continuous; proximal bracts orbiculate to ovate, lanceolate, oblong, or linear; corollas 10–22 mm; pollen sacs 0.7–1.6 mm. | → 17 |
17. Proximal bracts orbiculate to ovate; corollas lavender to bluish lavender or pinkish blue, glabrous internally; capsules 12–18(–20) mm. | P. buckleyi |
17. Proximal bracts ovate to oblong, lanceolate, or linear, rarely orbiculate; corollas blue, pinkish blue, bluish lavender, violet, or purple, hairy internally abaxially or glabrous; capsules 7–15 mm. | → 18 |
18. Corollas obscurely glandular externally or glabrous; cauline leaves 1–3 pairs; thyrses 3–15 cm, continuous, sometimes interrupted. | P. carnosus |
18. Corollas glabrous externally; cauline leaves 2–8 pairs; thyrses (2–)5–30(–37) cm, continuous or interrupted. | → 19 |
19. Staminodes 1–2 mm diam., distal 6–8 mm villous, hairs to 2.5 mm. | P. pachyphyllus |
19. Staminodes (0.2–)0.5–1.5 mm diam., distal 1.5–7 mm pilose to villous, hairs to 1.5 mm. | → 20 |
20. Cauline leaf blades: apices obtuse to acute, sometimes rounded or mucronate; peduncles to 12–28 mm; corolla throats 5–8 mm diam. | → 21 |
21. Cymes 1–3(or 4)-flowered; cauline leaves sessile; seeds 3.5–5 mm. | P. lentus |
21. Cymes (1 or)2–6-flowered; cauline leaves short-petiolate or sessile; seeds 2–4 mm. | → 22 |
22. Corollas bluish lavender to lavender, 15–22 mm; peduncles to 12 mm; calyx lobes ovate, 5–8(–12) mm, apices acuminate; staminodes: distal 2–5 mm densely villous, hairs yellowish, brownish, or orangish, to 1 mm. | P. immanifestus |
22. Corollas blue to violet, sometimes lavender, 12–20 mm; peduncles to 26 mm; calyx lobes ovate to lanceolate, (2.5–)4–7 mm, apices acute to acuminate or caudate; staminodes: distal 4–8 mm densely villous, hairs yellow to golden yellow, to 2.5 mm. | P. pachyphyllus |
20. Cauline leaf blades: apices acute to acuminate, sometimes mucronate (P. nitidus); peduncles to 3–4 mm; corolla throats 4–6 mm diam. | → 23 |
23. Cymes 2–5-flowered, verticillasters (2–)4–10; corolla tubes 4–6 mm; stems glabrous. | P. nitidus |
23. Cymes (2–)4–8(–12)-flowered, verticillasters (3–)5–15(–26); corolla tubes 5–9 mm; stems glabrous or scabrous. | → 24 |
24. Staminodes: distal 1.5–3.5 mm densely pilose, hairs to 0.6 mm; calyx lobes lanceolate, (3.2–)4.5–10 × 1.2–3.2(–3.8) mm; pollen sacs 0.7–1.3(–1.5) mm; Idaho, Nevada, Oregon, Washington. | P. acuminatus |
24. Staminodes: distal 4–6 mm sparsely villous, hairs to 1 mm; calyx lobes ovate to lanceolate, 4–8 × 1–2.5 mm; pollen sacs (0.9–)1.1–1.5 mm; Arizona, Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Utah, Wyoming. | P. angustifolius |
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