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Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

PENSTEMON BEARDTONGUE

Margriet Wetherwax & Noel H. Holmgren


Perennial herb to shrub. Leaf: generally opposite, entire to toothed; distal sessile. Inflorescence: panicle, raceme, cyme, or flowers in whorls; bracts generally small. Flower: calyx lobes 5, ± equal; corolla tube ± cylindric or lower side expanded, ± 2-lipped, generally pink or blue to purple (some red, yellow, or white), upper lip 2-lobed, external in bud; stamens 4, filament bases glabrous, attached to corolla at different levels, anther sacs 2, valves generally spreading ± flat at dehiscence; staminode attached near base of corolla tube, well developed, generally hairy adaxially; nectaries 2, at bases of upper stamens; stigma unlobed. Fruit: septicidal and sometimes also loculicidal at tip. Seed: generally many, irregularly angled.
250 species: North America, especially western United States. (Latin & Greek: almost thread, from stamen-like staminode) [Wolfe et al. 2006 Amer J Bot 93:1699–1713] Largest genus of flower plants endemic to North America. Penstemon subglaber, Penstemon strictus may persist in High Sierra Nevada, from commercial wildflower seed mixes or plantings; both native to Rocky Mountains.
Unabridged references: [Holmgren 1984 In Cronquist et al. Intermountain Flora 4:370–457]

Key to Penstemon

Key to Groups

1. Anther sacs not dehiscing full length (opening only partly)

2. Anther sacs dehiscing at distal end (proximal portion indehiscent) (subg. Habroanthus) ..... Group 1

2' Anther sacs dehiscing at proximal end (leaving distal portion indehiscent) (subg. Saccanthera) ..... Group 2

1' Anther sacs dehiscing full length, valves generally spreading widely apart

3. Corolla mouth closed by arched floor (subg. Cryptostemon) ..... P. personatus

3' Corolla mouth open

4. Anthers densely woolly (subg. Dasanthera) ..... Group 3

4' Anthers glabrous (subg. Penstemon) ..... Group 4

Group 1:

1. Corolla blue or blue-violet, tube ± abruptly expanded into throat, 6–13 mm wide at widest point

2. Calyx 3–4(5) mm; corolla throat 6–8 mm wide when pressed, floor hairy; anther sacs 1.6–2.2 mm ..... P. pahutensis

2' Calyx (4)6–13 mm; corolla throat 7–13 mm wide when pressed, floor glabrous; anther sacs 1.8–3 mm ..... P. speciosus

1' Corolla (orange-)red (yellow), tube gradually expanding into throat, 4–9 mm wide at widest point

3. Corolla 30–40 mm, distinctly 2-lipped, upper lip projecting, hood-like, lobes short, lower lip reflexed, lobes longer ..... P. labrosus

3' Corolla 24–33 mm, nearly radial, lobes ± equal, projecting ..... P. eatonii

4. Plant glabrous throughout ..... var. eatonii

4' Plant short-hairy ..... var. undosus

Group 2:

1. Corolla red to orange, lips long, lower lip strongly reflexed ..... P. rostriflorus

1' Corolla lavender, ± blue, or ± purple, lips short, lower lip projecting or spreading, not reflexed

2. Leaves sharply serrate; filaments white-hairy distally; corolla lobes finely ciliate ..... P. venustus

2' Leaves ± entire (weakly serrate in Penstemon parvulus, Penstemon purpusii); filaments glabrous distally; corolla lobes not finely ciliate

3. Staminode hairy; anthers glabrous on inner margins

4. Corolla 15–20 mm; leaves glabrous; anther sacs 1–1.3 mm ..... P. gracilentus

4' Corolla 24–34 mm; leaves hairy; anther sacs 1.4–1.9 mm

5. Leaves well-distributed on stems; anther sacs 1.7–1.9 mm, dehiscing < 1/3 length ..... P. papillatus

5' Leaves generally basal; anther sacs 1.4–1.7 mm, dehiscing for ± 1/2 length ..... P. scapoides

3' Staminode glabrous; anthers hairy on inner margins near filament attachment

6. Leaves generally basal; corolla floor hairy ..... P. caesius

6' Leaves well-distributed on stems; corolla floor glabrous

7. Herbage densely canescent-hairy; plant 0.5–2 dm ..... P. purpusii

7' Herbage glabrous to short-hairy; plant generally > 2 dm

8. Inflorescence glandular; peduncles widely spreading

9. Corolla 13–22 mm; anther sacs 1.2–2.2 mm, dehiscing for 2/5–3/5 length

10. Leaves thread-like, generally ± 0.5 mm wide; anther sacs 1.2–1.4 mm ..... P. filiformis

10' Leaves linear to (ob)lanceolate, 2–9 mm wide; anther sacs 1.5–2.2 mm ..... P. roezlii

9' Corolla 21–38 mm; anther sacs 1.7–3.2 mm, dehiscing for 3/5–4/5 length

11. Herbage glaucous, glabrous ..... P. neotericus

11' Herbage green, hairy, leaves sometimes glabrous ..... P. laetus

12. Calyx 8–14 mm, lobes narrowly lanceolate ..... var. leptosepalus

12' Calyx 4.7–9 mm, lobes generally lanceolate to ovate

13. Corolla throat open, lips ± spreading; anther sacs dehiscing for 3/5–2/3 length ..... var. laetus

13' Corolla throat ± narrowed at mouth, lips projecting; anther sacs dehiscing for 3/5–4/5 length ..... var. sagittatus

8' Inflorescence ± glabrous; peduncles appressed-ascending

14. Distal leaves widest at base, generally cordate-clasping; herbage generally glabrous, glaucous

15. Corolla 14–20 mm; anther sacs 1.4–2 mm ..... P. parvulus

15' Corolla 20–35 mm; anther sacs 1.8–3.5 mm ..... P. azureus

16. Calyx 5–7.5 mm, lobes ± ovate, long-tapered tips 1.5–3.2 mm; leaves linear, 4–9 cm, 2–7.5 mm wide ..... var. angustissimus

16' Calyx 3–6.5 mm, lobes (ob)lanceolate to round, pointed tip 0.2–1.5 mm; leaves lanceolate, 1–6.5 cm, 5–17 mm wide ..... var. azureus

14' Distal leaves tapered to base; herbage glabrous or hairy, rarely glaucous ..... P. heterophyllus

17. Leaves narrowly (ob)lanceolate, 2–7.5 mm wide, rarely with axillary leaf clusters ..... var. purdyi

17' Leaves linear to narrowly (ob)lanceolate, 0.5–5 mm wide, generally with axillary leaf clusters

18. Plant short-hairy ..... var. australis

18' Plant glabrous, sometimes proximal stems short-hairy ..... var. heterophyllus

Group 3:

1. Flower stem generally < 1.2 dm

2. Corolla blue-violet or blue-purple; staminode densely hairy; leaves green, glabrous ..... P. davidsonii var. davidsonii

2' Corolla rose, lavender, or violet; staminode glabrous to sparsely hairy; leaves glaucous, generally puberulent ..... P. rupicola

1' Flower stem 1.2–3 dm — corolla rose-red to dark rose-purple ..... P. newberryi

3. Corolla 27–35 mm, throat well-expanded, 7.5–12 mm wide when pressed, floor long-curly-hairy; stamens included ..... var. berryi

3' Corolla 20–30 mm, throat moderately expanded, 4.7–7.5 mm wide when pressed, floor short-hairy; stamens, at least longer pair, exserted

4. Corolla rose-red; leaves of flower stem << basal leaves ..... var. newberryi

4' Corolla dark rose-purple; leaves of flower stem barely reduced ..... var. sonomensis

Group 4:

1. Herbage hairy

2. Herbage glandular-hairy; corolla lobes glandular-hairy inside

3. Herbage densely glandular-hairy; flower stem erect, generally 4–7 dm, stout ..... P. sudans

3' Herbage sparsely glandular-hairy; flower stem generally decumbent at base, generally < 4 dm ..... P. deustus

4. Corolla 12–18 mm, upper lip white; leaves 8–18 mm wide ..... var. deustus

4' Corolla 9–15 mm, upper lip ± brown; leaves 3–28 mm wide

5. Leaves lanceolate, 2.5–8(14) mm wide; calyx 2.5–5 mm, lobes lanceolate, acute; corolla 10–12(15) mm ..... var. pedicellatus

5' Leaves ovate to ± round, 7–28 mm wide; calyx 3.5–6.5 mm, lobes narrowly lanceolate, sharply acute or long-tapered; corolla 9–11 mm ..... var. suffrutescens

2' Herbage nonglandular-hairy (distal stem, inflorescence occasionally also glandular); corolla lobes glabrous inside or corolla floor nonglandular-hairy

6. Inflorescence glabrous; calyx 1–4.5 mm; corolla 6–10 mm

7. Leaves generally all cauline, ± linear, folded lengthwise, arching-recurved ..... P. cinicola (2)

7' Leaves best developed on basal sterile stems, these (ob)lanceolate to obovate, cauline leaves ascending (folded lengthwise), not arching-recurved (see 29 for vars.) ..... P. procerus (2)

6' Inflorescence hairy, generally glandular; calyx 3–13 mm; corolla 10–30 mm

8. Calyx 3–8.5 mm

9. Basal leaves (15)20–75 mm, (2)4–32 mm wide, petioled, cauline leaves sessile ..... P. humilis var. humilis

9' Leaves similar throughout, 5–20 mm, 0.8–6 mm wide, petioled

10. Plant spreading to ascending, not mat-forming; stem 1–3 dm; calyx lobes ovate ..... P. californicus

10' Plant low, generally mat-forming; stem 0.5–1.5 dm; calyx lobes lanceolate ..... P. thompsoniae

8' Calyx (4.5)6–13 mm

11. Corolla gradually expanded into throat, throat 4–6 mm wide when pressed; staminode ± included, not coiled at tip

12. Anther sacs 0.6–0.7 mm, valves spreading widely; corolla 13–17 mm ..... P. calcareus

12' Anther sacs 1.1–1.4 mm, valves barely spreading; corolla 15–20 mm ..... P. monoensis

11' Corolla abruptly and widely expanded into throat, throat 7–12 mm wide (4–5 mm in Penstemon barnebyi) when pressed; staminode exserted, coiled at tip

13. Corolla 10–14 mm, throat 4–5 mm wide when pressed ..... P. barnebyi

13' Corolla 18–28 mm, throat 7–12 mm wide when pressed ..... P. janishiae

1' Herbage (proximal to inflorescence) glabrous

14. Inflorescence glabrous; leaf margin generally entire (serrate)

15. Corolla 17–34 mm

16. Anther sacs 0.6–1.2 mm; corolla floor glabrous

17. Corolla generally 13–20 mm, moderately expanded, lavender, magenta, or violet ..... P. patens (2)

17' Corolla 17–30 mm, cylindric or narrowly funnel-shaped, pink to red (± purple)

18. Corolla lobes projecting, not spreading, glabrous; leaves cordate-clasping ..... P. centranthifolius

18' Corolla lobes spreading, glandular; leaves not cordate-clasping ..... P. utahensis

16' Anther sacs 1.2–2.4 mm; corolla floor glabrous or hairy

19. Distal leaf pairs fused around stem, sharply serrate

20. Corolla 19–22 mm, bright pink; anther-sacs 1.3–1.6 mm ..... P. clevelandii var. connatus

20' Corolla 24–34 mm, blue-purple or blue; anther-sacs 1.8–2.4 mm ..... P. spectabilis var. spectabilis

19' Leaf pairs free (or barely fused in some hybrids), entire or weakly serrate

21. Leaves lanceolate to ovate, 10–35 mm wide; staminode included, glabrous — common hybrid ..... (see Penstemon centranthifolius description)

21' Leaves linear to narrowly lanceolate, 3–9 mm wide; staminode exserted, densely hairy ..... P. fruticiformis

22. Corolla 22–24 mm, throat 8–10 mm wide when pressed, glandular outside; calyx lobes ovate, generally 5–7.5 mm ..... var. amargosae

22' Corolla 24–28 mm, throat 10–14 mm wide when pressed, glabrous outside; calyx lobes widely ovate to ± round, generally 4.5–6 mm ..... var. fruticiformis

15' Corolla 6–17 mm

23. Openly branched shrub; leaves narrowly linear, generally rolled upward, generally < 1.4 mm wide ..... P. thurberi

23' Perennial herb, flowering stems generally little-branched; leaves generally lanceolate to oblanceolate to ovate (± linear in Penstemon cinicola), flat to folded, 1–22 mm wide

24. Leaves thick; anther sacs 1–1.2 mm; corolla floor glabrous ..... P. patens (2)

24' Leaves ± thin; anther sacs 0.3–1 mm; corolla floor hairy

25. Corolla 9–17 mm (if < 10 mm anther sacs 0.5–0.8 mm)

26. Plant 8–12 cm; distal cauline leaves ovate to ± round, 10–20 mm; anther sacs ± 0.4 mm; calyx 2.5–3 mm ..... P. tracyi

26' Plant 15–60 cm; distal cauline leaves (ob)lanceolate, 15–70 mm; anther sacs 0.5–1 mm; calyx 3–5 mm

27. Stem base generally buried in sand; proximal-most cauline leaves scale-like ..... P. albomarginatus

27' Stem base above ground; proximal cauline leaves well developed ..... P. rydbergii var. oreocharis

25' Corolla 6–10 mm; anther sacs 0.3–0.5 mm

28. Leaves generally all cauline, ± linear, folded lengthwise and arching-recurved ..... P. cinicola (2)

28' Leaves best developed on basal, sterile stems, (ob)lanceolate to obovate, cauline leaves ascending, not arching-recurved ..... P. procerus (2)

29. Plant 10–40 cm; distal cauline leaves 10–45 mm, 3–10 mm wide ..... var. brachyanthus

29' Plant 5–12 cm; distal cauline leaves generally 5–20 mm, 1–5.5 mm wide ..... var. formosus

14' Inflorescence generally glandular or glandular-hairy (except occasionally Penstemon stephensii inflorescence glabrous); leaf margin ± serrate or dentate (except Penstemon heterodoxus, Penstemon incertus, occasionally Penstemon clevelandii)

30. Distal leaf pairs fused around stem

31. Anther sacs 0.8–1.3 mm, valves spreading flat — desert areas

32. Corolla generally 17–25 mm, throat 5–9 mm wide when pressed; lower lip strongly lined; anther sacs 1.1–1.3 mm ..... P. pseudospectabilis

32' Corolla generally < 20 mm, throat 4–6 mm wide when pressed, lower lip lacking prominent guide-lines; anther sacs 0.8–1.1 mm ..... P. stephensii

31' Anther sacs 1.3–2.4 mm, valves hardly spreading (except Penstemon bicolor)

33. Corolla 18–24(27) mm; anther sacs 1.3–2 mm ..... P. bicolor

33' Corolla 24–34 mm; anther sacs 1.8–2.4 mm

34. Corolla pale pink to lavender-pink; staminode densely hairy, exserted ..... P. palmeri var. palmeri

34' Corolla blue-purple or blue; staminode glabrous, included ..... P. spectabilis var. subviscosus

30' Leaves free, not fused around stem

35. Corolla 10–18 mm

36. Leaves ± serrate, distal cordate-clasping; upper side of corolla abruptly expanded ..... P. anguineus

36' Leaves entire, distal not cordate-clasping; upper side of corolla cylindric to moderately expanded ..... P. heterodoxus

37. Plant 5–20 cm; inflorescence of 1(2) flower clusters ..... var. heterodoxus

37' Plant generally > 20 cm; inflorescence generally of 2–6 flower clusters

38. Inflorescence strongly glandular ..... var. cephalophorus

38' Inflorescence moderately glandular ..... var. shastensis

35' Corolla 18–35 mm

39. Leaves thin; upper side of corolla tube abruptly expanded; calyx 6–12 mm ..... P. rattanii

40. Calyx lobes ovate, obtuse or rounded at tip, calyx 6–7 mm ..... var. kleei

40' Calyx lobes lanceolate, acute or long-tapered at tip, calyx 6–12 mm ..... var. rattanii

39' Leaves thick; corolla gradually expanded or lower side ± abruptly expanded; calyx 3–8.5 mm

41. Leaves linear to narrowly lanceolate, 1.5–7 mm wide ..... P. incertus

41' Leaves lanceolate to widely ovate, 10–60 mm wide

42. Corolla gradually expanded, throat 4.5–9 mm wide when pressed

43. Corolla 24–30 mm; anther sacs 1.2–1.6 mm; main upper leaves 45–90 mm — common hybrid ..... (see Penstemon centranthifolius description)

43' Corolla 18–24 mm; anther sacs 0.8–1.3 mm; main distal leaves 20–60 mm ..... P. clevelandii (in part)

44. Leaves entire to moderately serrate; staminode glabrous or sparsely hairy ..... var. clevelandii

44' Leaves sharply serrate; staminode densely hairy ..... var. mohavensis

42' Corolla abruptly expanded (except Penstemon floridus var. austinii), throat 6–20 mm wide when pressed

45. Staminode included, glabrous; anther-sacs 1.3–1.9 mm ..... P. floridus

46. Corolla 21–27 mm, throat 6–11 mm wide when pressed, mouth perpendicular to tube, tube 6–8 mm ..... var. austinii

46' Corolla 24–30 mm, ± abruptly expanded to throat, 10–16 mm wide when pressed, mouth oblique to tube, tube 7–12 mm ..... var. floridus

45' Staminode exserted, densely hairy; anther-sacs 1.6–2.2 mm ..... P. grinnellii

47. Plant 10–60 cm; young branches light green; corolla 22–30 mm, ± white, tinged pink or lavender ..... var. grinnellii

47' Plant 45–85 cm; young branches glaucous; corolla 26–35 mm, blue-violet ..... var. scrophularioides

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