Penstemon glaber
Penstemon subg. Penstemon
sawsepal penstemon, southern smooth beardtongue, western smooth beardtongue
ascending, (10–)50–65(–80) cm, glabrous or puberulent to pubescent, not glaucous.
basal and cauline, or basal absent or reduced, not leathery, glabrous or puberulent to pubescent, not glaucous;
basal and proximal cauline 20–80(–155) × 5–20(–45) mm, blade obovate to oblanceolate or lanceolate, base tapered, margins entire, usually undulate, apex obtuse to acute, sometimes mucronate;
cauline (2 or)3–6(–8) pairs, sessile, 27–120(–150) × (6–)22–35(–43) mm, blade lanceolate, base truncate to cordate, apex obtuse to acute.
continuous, secund, (3–)6–26(–30) cm, axis glabrous or puberulent, verticillasters (3–)5–12, cymes 2–4-flowered, 2 per node;
proximal bracts ovate to lanceolate, 14–100 × 2–36 mm;
peduncles and pedicels glabrous or puberulent, peduncles to 71 mm, pedicels 4–14 mm.
calyx lobes ovate to orbiculate, 2–11 × 1.3–5.5 mm, glabrous or puberulent;
corolla blue to violet, with reddish purple nectar guides, ventricose, 24–48 mm, glabrous externally, glabrous internally or sparsely to moderately white-lanate internally abaxially, tube 5–12 mm, throat gradually inflated, slightly constricted at orifice, 8–13(–18) mm diam., rounded abaxially;
stamens included or longer pair reaching orifice, pollen sacs divergent, navicular, 1.4–2.5(–2.8) mm, dehiscing incompletely, connective not splitting, sides sparsely to moderately hirsute, hairs white or tan, to 0.5 mm, rarely glabrous, sutures denticulate, teeth to 0.2 mm;
staminode (15–)18–22 mm, included or barely exserted, 0.6–1.3 mm diam., tip straight to recurved, rounded to distinctly bifurcate at apex, glabrous or distal 1–2 mm sparsely lanate, hairs pale yellow, to 1.5 mm;
style 18–20 mm.
pollen sacs navicular, navicular-sigmoid, saccate, or explanate, dehiscing completely or incompletely, connective splitting or not, sides glabrous or hairy, hairs not concealing surface, sutures smooth, papillate, or denticulate;
staminode included to exserted, if included, length 3/4+ times corolla throat.
10–17 × 5–8 mm.
angled or rounded, rarely angled-elongate, reniform, or disciform, wings absent.
Penstemon glaber
Penstemon subg. Penstemon
Varieties 3 (3 in the flora).
The Penstemon glaber complex has been treated with as many as four species (F. W. Pennell 1920b) or one variable species as treated herein. M. K. W. Latady (1985) found clinal variation in most morphologic characters used to distinguish taxa in the complex and recognized only one species and two varieties: var. glaber (including var. alpinus) in the plains and mountains from southeastern Montana south to central Colorado; and var. brandegeei, in the mountains from central Colorado south to north-central New Mexico. A case for recognizing var. alpinus, as is done here, can be made on morphological, phenological, and ecological grounds.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species ca. 270 (229 in the flora).
Following the recommendation of A. D. Wolfe et al. (2006), subg. Penstemon is expanded here to include species of Penstemon not included in subg. Dasanthera. Molecular data indicate that some sections as usually circumscribed are paraphyletic. Absent a robust phylogeny for Penstemon, a morphology-based classification is followed here with minor adjustments. As circumscribed here, subg. Penstemon comprises 16 sections, 15 in the flora area.
Section Leptostemon Trautvetter includes 27 species from Mexico and Guatemala. Among its members are Penstemon campanulatus (Cavanilles) Willdenow, P. gentianoides (Kunth) Poiret, and P. hartwegii Bentham, three red- or purple-flowered species popular among European plant breeders in the nineteenth century and used in the development of European hybrid penstemons (R. Nold 1999; D. Lindgren and E. Wilde 2003).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Calyx lobes 2–4.8 mm, apices rounded or abruptly short-acuminate; staminode apices rounded. | var. glaber |
1. Calyx lobes 3.8–11 mm, apices long-acuminate; staminode apices rounded or bifurcate. | → 2 |
2. Staminode apices rounded or bifurcate; corollas 24–35 mm; stems glabrous or puberulent proximally. | var. alpinus |
2. Staminode apices usually bifurcate; corollas 27–48 mm; stems puberulent to pubescent proximally. | var. brandegeei |
Key to Sections of subg. Penstemon
1. Cauline leaf blade margins deeply pinnatifid to nearly pinnatisect. | P. sect. Dissecti |
1. Cauline leaf blade margins entire or toothed, rarely laciniate-pinnatifid. | → 2 |
2. Subshrubs or shrubs; staminodes glabrous; corollas pink, red, scarlet, or magenta, rarely lavender or violet. | → 3 |
3. Cauline leaf blades linear and pollen sacs explanate. | P. sect. Ambigui |
3. Cauline leaf blades obovate, ovate, oblanceolate, lanceolate, elliptic, or linear; pollen sacs navicular, saccate, subexplanate, or explanate. | → 4 |
4. Pollen sacs subexplanate to explanate, opposite; corollas weakly ventricose; thyrses cylindric; leaves glaucous. | P. sect. Petiolati |
4. Pollen sacs saccate or navicular, parallel or divergent; corollas salverform or funnelform; thyrses secund; leaves not glaucous. | → 5 |
5. Cauline leaf margins toothed or entire; corollas funnelform, glandular-pubescent internally abaxially and adaxially; cymes 1 per node; Texas. | P. sect. Baccharifolii |
5. Cauline leaf margins entire; corollas salverform, hairy internally abaxially; cymes 2 per node; Arizona, California, Colorado, Nevada, New Mexico, Utah. | P. sect. Bridgesiani |
2. Herbs, shrubs, or subshrubs; staminodes hairy distally or glabrous; corollas usually white, lavender, lilac, blue, violet, purple, ochroleucous, yellow, orange, or crimson, if pink, red, scarlet, or magenta, herbs and/or staminodes hairy, or both. | → 6 |
6. Pollen sacs saccate, dehiscing incompletely, distal 1/5–2/3 indehiscent, connectives splitting, rarely not. | → 7 |
7. Pollen sac sutures papillate; herbs. | P. sect. Penstemon |
7. Pollen sac sutures denticulate; herbs or subshrubs. | → 8 |
8. Herbs; pollen sac sides glabrous; staminodes glabrous, tips recurved; cauline leaf blade margins entire; thyrses interrupted. | P. sect. Chamaeleon |
8. Herbs or subshrubs; pollen sac sides glabrous or hairy; staminodes glabrous or hairy distally, tips straight; cauline leaf blade margins entire or toothed, rarely laciniate-pinnatifid; thyrses interrupted or continuous. | P. sect. Saccanthera |
6. Pollen sacs navicular, navicular-sigmoid, sigmoid, subexplanate, or explanate, dehiscing completely, if incompletely proximal 1/5–1/2 indehiscent and/or connectives not splitting. | → 9 |
9. Pollen sacs dehiscing incompletely, proximal 1/5–1/2 indehiscent and/or connectives not splitting. | → 10 |
10. Corollas red to scarlet or orange, rarely yellow, glabrous externally. | P. sect. Elmigera |
10. Corollas white to pink, lavender, lilac, blue, violet, or purple, glandular-pubescent or glabrous externally, if corollas reddish pink or rose red, glandular-pubescent externally. | → 11 |
11. Pollen sacs: connectives not splitting, sutures papillate, sides glabrous; corollas tubular-funnelform. | P. sect. Cristati |
11. Pollen sacs: proximal 1/5–1/3 indehiscent and/or connectives not splitting, sutures denticulate, sometimes papillate or smooth, sides glabrous or hairy; corollas funnelform, ventricose, or ventricose-ampliate. | P. sect. Glabri |
9. Pollen sacs dehiscing completely (rarely connectives not splitting in P. incertus). | → 12 |
12. Staminodes glabrous; pollen sacs parallel to divergent, sutures denticulate, teeth to 0.2–0.3 mm. | P. sect. Chamaeleon |
12. Staminodes hairy distally, sometimes glabrous; pollen sacs opposite or divergent, rarely parallel, sutures smooth, papillate, or denticulate, teeth to 0.1–0.2 mm. | → 13 |
13. Subshrubs; leaves cauline, rarely basal and cauline, blade margins entire; stems not glaucous; corollas 2-ridged abaxially. | P. sect. Caespitosi |
13. Herbs, shrubs, or subshrubs; leaves basal and cauline, sometimes basal few or absent, blade margins entire or toothed, if shrubs or subshrubs, leaves basal and cauline or leaf blade margins toothed or stems glaucous; corollas rounded to 2-ridged abaxially. | → 14 |
14. Stems and/or leaves and/or thyrse axes hairy; leaf blades not (or rarely) glaucous, not (or rarely) leathery. | → 15 |
15. Corollas glabrous externally, ventricose or ventricose-ampliate. | P. sect. Glabri |
15. Corollas glandular-pubescent externally, if glabrous then tubular, tubular-funnelform, or funnelform. | → 16 |
16. Corolla throats rounded abaxially, sometimes slightly 2-ridged; staminodes: distal (40–)50–100% hairy, hairs to 4 mm, exserted, sometimes reaching orifice or included, tips straight to recurved or coiled; seeds 1.4–4.8 mm, brown, dark brown, or black. | P. sect. Cristati |
16. Corolla throats slightly to prominently 2-ridged abaxially, rarely rounded; staminodes: distal 5–60(–90)% hairy, hairs to 3 mm, sometimes glabrous, included or reaching orifice, sometimes exserted, tips straight to recurved; seeds 0.4–2(–3.5) mm, tan, brown, gray, or black. | P. sect. Penstemon |
14. Stems, leaves, and thyrse axes glabrous, rarely scabrous; leaf blades glaucous, rarely not, leathery, rarely not. | → 17 |
17. Shrubs or subshrubs; stamen filaments: shorter pair glandular-puberulent proximally. | P. sect. Spectabiles |
17. Herbs; stamen filaments glabrous. | → 18 |
18. Leaf blade margins toothed. | P. sect. Spectabiles |
18. Leaf blade margins entire (rarely remotely and obscurely toothed in P. parryi). | → 19 |
19. Stamens exserted; corollas red, 32–36 mm. | P. sect. Coerulei |
19. Stamens included or longer pair reaching orifice, rarely exserted; corollas lavender to blue, violet, purple, white, pink, lilac, red, scarlet, crimson, magenta, orange, yellow, or ochroleucous, 6–33 mm. | → 20 |
20. Basal and proximal cauline leaf blades linear, 0.5–1.5 mm wide. | P. sect. Cristati |
20. Leaf blades ovate, obovate, lanceolate, oblanceolate, spatulate, trullate, oblong, or elliptic, rarely linear, 1–70 mm wide. | → 21 |
21. Pollen sacs 0.3–1.2 mm, opposite; corollas 7–22 mm, throats 2-ridged abaxially, sometimes rounded. | P. sect. Penstemon |
21. Pollen sacs 0.6–3 mm, opposite, divergent, or parallel; corollas 10–48 mm, throats rounded abaxially, rarely slightly 2-ridged. | → 22 |
22. Pollens sacs navicular; corollas glabrous externally, rarely obscurely glandular (P. carnosus). | P. sect. Coerulei |
22. Pollen sacs explanate, sometimes navicular; corollas glandular-pubescent externally, if glabrous staminode papillate distally, papillae to 0.2 mm. | P. sect. Gentianoides |
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