Penstemon strictiformis
Penstemon subg. Penstemon
Mancos penstemon, stiff beardtongue, stiff penstemon
ascending to erect, (11–)16–55(–70) cm, glabrous, not glaucous.
basal and cauline, ± leathery or not, glabrous, not glaucous;
basal and proximal cauline 60–90(–150) × 5–12 mm, blade oblanceolate to lanceolate, base tapered, margins entire, apex acute;
cauline 3–5 pairs, sessile, 18–80 × 3–18 mm, blade lanceolate, base tapered to truncate or clasping, apex acute.
continuous or interrupted, ± secund, 5–40 cm, axis glabrous, verticillasters 4–8(–12), cymes 2- or 3(–5)-flowered, 2 per node;
proximal bracts lanceolate, 12–46(–115) × 2–15 mm, apex acuminate;
peduncles and pedicels glabrous or ± glandular, peduncles to 20 mm, pedicels 2–13(–18) mm.
calyx lobes ovate to lanceolate, (4.5–)6–8(–9) × 2–3 mm, apex acuminate to caudate, glabrous or ± glandular proximally;
corolla lavender to blue, without nectar guides, ventricose, (19–)25–32 mm, glabrous externally, glabrous internally, tube 5–7 mm, throat gradually to abruptly inflated, not constricted at orifice, 7–10 mm diam., slightly 2-ridged abaxially;
stamens: longer pair slightly exserted, pollen sacs divergent, navicular-sigmoid, 1.3–2.3 mm, dehiscing incompletely, proximal 1/5–1/4 indehiscent, connective not splitting, sides sparsely to densely lanate, hairs white, to 1 mm, sutures denticulate, teeth to 0.1 mm;
staminode (8–)11–15 mm, included, 0.5–0.1(–1.2) mm diam., tip straight to recurved, distal (2–)4–5 mm sparsely to moderately villous, hairs yellow or white, to 1 mm;
style (11–)13–21 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.
7–11 × 4–6 mm.
angled or rounded, rarely angled-elongate, reniform, or disciform, wings absent.
Penstemon strictiformis
Penstemon subg. Penstemon
Plants of Penstemon strictiformis from southwestern Colorado (Montezuma County) and northwestern New Mexico (San Juan County) closely match the type, with large corollas, broad calyx lobes, and large pollen sacs. Plants from southeastern Utah have relatively smaller corollas, narrower calyx lobes, and smaller pollen sacs.
Penstemon strictiformis often is confused with P. strictus; many specimens from southwestern Colorado are difficult to place with certainty due to morphologic intermediacy.
(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.)
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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