Jepson Flora Project: Jepson Interchange    

The Jepson Manual: Higher Plants of California

  • Up-to-date information about California vascular plants is available from the Jepson eFlora.

Names are linked to treatments from the Manual

Key to PENSTEMON Key to Groups

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Anther sacs not dehiscing full length (opening only partly)
    2. Anther sacs dehiscing at distal end (proximal portion indehiscent); perennial herb (subg. Habroanthus)
Group 1
    2' Anther sacs dehiscing at proximal end (leaving distal portion indehiscent); subshrubs (subg. Saccanthera)
Group 2
  1' Anther sacs dehiscing full length, valves generally spreading widely apart
    3. Corolla mouth closed by arched floor, hiding densely hairy throat interior (subg. Cryptostemon)
P. personatus
    3' Corolla mouth open, exposing glabrous interior of throat (corolla floor frequently hairy)
      4. Anthers densely woolly; shrubs (subg. Dasanthera)
Group 3
      4' Anthers glabrous; perennial herb or subshrubs (subg. Penstemon)
Group 4

Key to PENSTEMON Group 1 (subg. Habroanthus)

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Corolla blue or blue-violet, tube ± abruptly expanded into throat, 6–13 mm wide at widest point
    2. Calyx 3–5 mm; corolla throat 6–8 mm wide when pressed, floor hairy; anther sacs 1.6–2.2 mm
P. pahutensis
    2' Calyx 4–13 mm; corolla throat 7.5–13 mm wide when pressed, floor glabrous; anther sacs 1.8–3 mm
P. speciosus
  1' Corolla red, 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, short-lobed, lower lip reflexed, longer-lobed
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

Key to PENSTEMON Group 2 (subg. Saccanthera)

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Corolla red to orange, lips long, lower lip strongly reflexed
P. rostriflorus
  1' Corolla lavender, bluish, or purplish, 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 P. parvulus, P. 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 finely 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, 0.4–1.5 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 2/3–3/5 length
var. laetus
                    13' Corolla throat somewhat narrowed at mouth, lips ± projecting; anther sacs dehiscing for 3/5– 4/5 length
var. sagittatus
            8' Inflorescence glabrous, peduncles appressed-ascending
              14. Upper leaves widest near 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 tips 0.2–1.5 mm; leaves (ob)lanceolate, 1–6.5 cm, 5–17 mm wide
var. azureus
              14' Upper 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' Most leaves linear (some narrowly (ob)lanceolate), 0.5–5 mm wide, generally with axillary leaf clusters
                  18. Plant short-hairy
var. australis
                  18' Plant glabrous, sometimes lower stems short-hairy
var. heterophyllus

Key to PENSTEMON Group 3 (subg. Dasanthera)

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Flower stems generally < 1.2 dm
    2. Corolla blue-violet or blue-purple; staminode densely hairy; leaves green, glabrous
P. davidsonii
    2' Corolla rose, lavender, or violet; staminode glabrous to sparsely hairy; leaves glaucous, generally puberulent
P. rupicola
  1' Flower stems 1.2–3 dm — corolla rose-red to rose-purple
P. newberryi
    3. Corolla 27–35 mm, throat well expanded, 7.5–12 mm wide when pressed, floor ± long-wavy-hairy; anthers included
var. berryi
    3' Corolla 20–30 mm, throat moderately expanded, 4.7–7.5 mm wide when pressed, floor short-hairy; anthers, 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

Key to PENSTEMON Group 4 (subg. Penstemon)

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Herbage hairy
    2. Herbage glandular-hairy; corolla lobes glandular-hairy inside
      3. Herbage densely glandular-hairy; flower-stems erect, generally > 4 dm, stout
P. sudans
      3' Herbage sparsely glandular-hairy; flower-stems generally decumbent at base, generally < 4 dm
P. deustus
        4. Leaves lanceolate, generally < 8 mm wide; calyx generally < 4 mm, lobes lanceolate, acute; corolla 10–15 mm
var. pedicellatus
        4' Leaves ovate to ± round, 7–28 mm wide; calyx generally > 4 mm, lobes narrowly lanceolate, sharply acute or long-tapered; corolla 9–11 mm
var. suffrutescens
    2' Herbage nonglandular-hairy; corolla lobes glabrous inside or corolla floor nonglandular-hairy
      5. Inflorescence glabrous; calyx 1.5–4.5 mm; corolla 6–10 mm
        6. Leaves generally all cauline, linear or narrowly lanceolate, generally folded lengthwise and arching-recurved
2 P. cinicola
        6' Leaves best developed on basal sterile stems, these (ob)lanceolate to obovate, cauline leaves ascending, rarely folded lengthwise, not arching-recurved (for vars. see 29)
2 P. procerus
      5' Inflorescence hairy, generally glandular; calyx 3–12 mm; corolla 10–30 mm
        7. Calyx 3–6 mm
          8. Corolla 20–25 mm, floor arched, closing off throat, hiding stamens and densely hairy interior
P. personatus
          8' Corolla 10–18 mm, floor not closing off throat, stamens and glabrous throat interior exposed
            9. Leaves at base of plant 15–75 mm, 2–32 mm wide, petioled (upper leaves sessile)
P. humilis
            9' Leaves similar throughout, 8–20 mm, 0.8–6 mm wide, petioled
              10. Plant ± erect, not mat-forming, stems 1–3 dm; calyx lobes ovate
P. californicus
              10' Plant low, generally mat-forming, stems 0.5–1.5 dm; calyx lobes lanceolate
P. thompsoniae
        7' Calyx 6–12 mm
          11. Corolla gradually expanded into 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, 7–12 mm wide (4–5 mm in P. 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 (below inflorescence) glabrous
    14. Inflorescence glabrous; leaf margin generally entire
      15. Corolla 17–34 mm
        16. Anther sacs 0.6–1.2 mm; corolla floor glabrous
          17. Corolla generally < 17 mm, moderately expanded, lavender, magenta, or violet
2 P. patens
          17' Corolla > 17 mm, cylindric or narrowly funnel-shaped, red
            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. Upper 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, bluish 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 P. centranthifolius)
            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 inward, generally < 1.4 mm wide
P. thurberi
        23' Perennial, flower-stems generally little-branched; leaves generally lanceolate to ovate (linear in P. cinicola), flat to folded, 1–22 mm wide
          24. Leaves thick; anther sacs 1–1.2 mm; corolla floor glabrous
2 P. patens
          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; upper cauline leaves ovate to ± round, 10–20 mm; anther sacs < 0.5 mm; calyx 2.5–3 mm
P. tracyi
              26' Plant 15–60 cm; upper cauline leaves (ob)lanceolate, 15–70 mm; anther sacs 0.5–1 mm; calyx 3–5 mm
                27. Stem base generally buried in sand; lower cauline leaves scale-like
P. albomarginatus
                27' Stem base aboveground; lower 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 to narrowly lanceolate, generally folded lengthwise and arching-recurved
2 P. cinicola
              28' Leaves best developed on basal, sterile stems, (ob)lanceolate to obovate, cauline leaves ascending, not arching-recurved
P. procerus
                29. Plant 10–40 cm; upper cauline leaves 10–45 mm, 3–10 mm wide
var. brachyanthus
                29' Plant 5–12 cm; upper cauline leaves generally 5–20 mm, 1–5.5 mm wide
var. formosus
    14' Inflorescence glandular-hairy; leaf margin toothed (except P. heterodoxus)
      30. Upper leaf pairs fused around stem
        31. Anther sacs 0.8–1.3 mm, valves spreading flat
          32. Corolla generally > 20 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 P. bicolor)
          33. Corolla 18–27 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
            34' Corolla bluish purple or blue; staminode glabrous, included
P. spectabilis var. subviscosus
      30' Leaves free, not fused around stem
        35. Corolla 10–18 mm
          36. Leaves ± toothed, upper cordate-clasping; upper side of corolla abruptly expanded
P. anguineus
          36' Leaves entire, upper not cordate-clasping; upper side of corolla moderately expanded
P. heterodoxus
            37. Plant 5–20 cm; inflorescence of 1(2) flower cluster
var. heterodoxus
            37' Plant generally > 20 cm; inflorescence generally of > 2 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, calyx 6–7 mm
var. kleei
            40' Calyx lobes lanceolate, acute or long-tapered, 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 P. centranthifolius)
                43' Corolla 18–24 mm; anther sacs 0.8–1.3 mm; main upper leaves 20–55 mm
P. clevelandii
                  44. Leaves entire to moderately serrate; staminode glabrous or sparsely hairy
var. clevelandii
                  44' Leaves sharply serrate; staminode densely hairy
var. mohavensis
              42' Corolla strongly expanded, 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, expanded gradually to 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, hairy; anther-sacs 1.6–2.2 mm
P. grinnellii
                  47. Plant 10–60 cm; young branches light green; corolla 22–30 mm, whitish, tinged pink or lavender
var. grinnellii
                  47' Plant 45–85 cm; young branches glaucous; corolla 26–35 mm, tinged (blue-) violet
var. scrophularioides

Comments or questions on page
University & Jepson Herbaria Home Page |
General Information | University Herbarium | Jepson Herbarium |
Visiting the Herbaria | On-line Resources | Research |
Education | Related Sites |

Copyright by the Regents of the University of California