Jepson eFlora
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Key to Erigeron

View taxon page for Erigeron

(For a list of species in Erigeron, use the above link.)

Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.

1. Heads discoid, disciform, or inconspicuously radiate, rays 0 to barely exceeding involucre

2. Pistillate flowers present

3. Pistillate flowers of 2 kinds, those in outer zone with rays 3–4.5 mm, those in inner zone without rays ..... E. nivalis (2)

3' Pistillate flowers ± all alike, generally not in 2 zones

4. Heads 1; stem simple

5. Annual or biennial; pappus bristles 6–9(12) ..... E. divergens (3)

5' Perennial herb; pappus bristles 12–25

6. Leaves (1)2–3(4)-ternately dissected ..... E. compositus (2)

6' Leaves entire

7. Stem minutely glandular; disk corolla generally abruptly inflated to throat; fruit base ringed ± white; outer pappus of narrow scales or obvious bristles ..... E. aphanactis var. congestus

7' Stem glandless; disk corolla narrowly funnel-shaped; fruit base ringed ± yellow; outer pappus of minute bristles ..... E. chrysopsidis var. austiniae

4' Heads 1–many; stem often branched

8. Rays 1–3 mm

9. Inflorescence panicle-like, heads many; rays <= 1 mm; involucre glabrous or sparsely strigose to minutely bristly; central colored part of middle phyllaries resin-filled, ± red-brown when dry ..... E. canadensis (3)

9' Inflorescence generally raceme-like, heads 1–12; rays 2–3 mm; involucre ± rough-hairy; central colored part of middle phyllaries not resin-filled, not red-brown when dry ..... E. lonchophyllus (2)

8' Rays 0–1 mm

10. Central stem and axes of stiffly ascending branches generally strongly dominant; inflorescence generally raceme- or panicle-like, often many-headed; disk flowers 6–25

11. Central stem often overtopped by distal branches in age; plant ± gray-hairy; heads ± long-peduncled, generally in raceme-like clusters; receptacle (2.5)3–5 mm diam in fruit; pistillate flowers 60–150+; phyllaries generally minutely bristly and/or densely strigose; pappus 3–4+ mm ..... E. bonariensis

11' Central stem generally exceeding distal branches in age; plant green, glabrous to hairy; heads ± short-peduncled in panicle-like clusters; receptacle 1–3 mm diam in fruit; pistillate flowers 20–90+; phyllaries glabrous to densely strigose or densely bristly; pappus 2–3(4) mm

12. Leaf ± long-bristly-ciliate; phyllaries generally glabrous, occasionally sparsely strigose; central colored part of middle phyllaries narrower than light-colored margin, resin-filled, ± red-brown when dry; ray 0.3–1 mm; disk corolla generally 4-lobed; fruit uniformly pale tan to light gray-brown ..... E. canadensis (3)

12' Leaf margin generally ± fine-strigose; phyllaries glabrous to densely strigose or spreading-hairy; central part of middle phyllaries generally wider than lighter margin, not red-brown or resin-filled when dry; ray 0–0.3 mm; disk corolla generally 5-lobed; fruit pale tan, generally some in head with ± red veins ..... E. sumatrensis

10' Central stem and axes of ascending branches not strongly dominant, plant ± openly branched; inflorescence ± cyme-like, often 1–few-headed; disk flowers generally >= 25

13. Perennial herb; pappus bristles 12–17 ..... E. aphanactis var. aphanactis

13' Annual, biennial or short-lived perennial herb; pappus bristles 6–9(12) or 15–20

14. Pappus bristles 15–20; biennial or short-lived perennial herb ..... E. calvus

14' Pappus bristles 6–9(12); annual or biennial ..... E. divergens (3)

2' Pistillate flowers 0

15. Basal leaves present at flower; cauline leaves generally much-reduced or 0 distally

16. Caudex simple ..... E. lassenianus var. deficiens

16' Caudex branched

17. Stem ascending, 15–40 cm, occasionally sparsely spreading-hairy; caudex branches slender, rhizome-like; basal leaves elliptic to oblanceolate to spoon-shaped ..... E. supplex

17' Stem erect, 4–15 cm, ± glabrous to densely strigose; caudex branches short, stout; basal leaves ± linear ..... E. bloomeri

18. Herbage and phyllaries strigose ..... var. bloomeri

18' Herbage and phyllaries ± glabrous ..... var. nudatus

15' Basal leaves 0 at flower; cauline leaves generally evenly sized and spaced

19. Glandless stem hairs ± spreading

20. Stem hairs dense, short, stiff, slightly reflexed, ± gray ..... E. inornatus var. keilii

20' Stem hairs sparse to dense, long, ± crinkly-spreading, white

21. Stem 30–90 cm, ascending to erect; leaves 20–40 mm; involucre 12–15 mm diam ..... E. biolettii (2)

21' Stem 5–30 cm, decumbent to ascending; leaves 7–25 mm; involucre 7–15 mm diam

22. Inner phyllaries 3.5–5 mm ..... E. miser

22' Inner phyllaries 5.5–7 mm ..... E. petrophilus

23. Herbage ± glandless; hairs stiff, straight or curved ..... var. viscidulus

23' Herbage densely glandular; glandless hairs generally loose, often crinkly

24. Phyllary tips obviously widened and ± purple ..... var. petrophilus

24' Phyllary tips not widened or purple ..... var. sierrensis

19' Glandless stem hairs 0–sparse, appressed

25. Phyllaries generally glabrous ..... E. inornatus (in part)

26. Stem 10–20 cm, decumbent to ascending; proximally ± reflexed-hairy; proximal and middle leaf blades and margins stiffly spreading-hairy and -ciliate; inner phyllaries 5–6.5 mm ..... var. calidipetris

26' Stem 30–90 cm, ascending; proximally ± glabrous or appressed-hairy; proximal and middle leaf blades and margins generally short-strigose or ± glabrous; inner phyllaries 4.5–5.5 mm ..... var. inornatus

25' Phyllaries glandular (sometimes also with sparse, glandless hairs)

27. Herbage glandular; leaf narrowly oblanceolate ..... E. biolettii (2)

27' Herbage glandless; leaf thread-like to oblanceolate

28. Leaf ± oblanceolate; stem long-ascending from woody taproot ..... E. inornatus var. inornatus

28' Leaf thread-like to linear; stem from stout woody caudex or thin, rhizome-like caudex branches

29. Stem 30–90 cm, many, from stout woody caudex ..... E. greenei

29' Stem 8–20(30) cm, 1, from slender, rhizome-like caudex branches ..... E. reductus

30. Phyllary tips generally ± purple (variable n San Francisco Bay Area); pappus bristles 38–61 ..... var. angustatus

30' Phyllary tips ± green; pappus bristles 20–30 ..... var. reductus

1' Heads conspicuously radiate, rays exceeding to much-exceeding involucre

31. Pistillate flowers of 2 kinds, those in outer zone with rays 3–4.5 mm, those in inner zone without rays ..... E. nivalis (2)

31' Pistillate flowers all alike, not in 2 zones

32. Rays 1–3 mm

33. Inflorescence panicle-like, heads many; rays <= 1 mm; involucre glabrous or sparsely strigose to minutely bristly; central colored part of middle phyllaries resin-filled, ± red-brown when dry ..... E. canadensis (3)

33' Inflorescence generally raceme-like, heads 1–12; rays 2–3 mm; involucre ± rough-hairy; central colored part of middle phyllaries not resin-filled, not red-brown when dry ..... E. lonchophyllus (2)

32' Rays 4–25 mm

34. Annual (biennial to short-lived perennial herb) from slender taproot or shallow fibrous roots (see also Erigeron philadelphicus var. philadelphus)

35. Ray flower pappus 0; plant fibrous-rooted

36. Leaves generally coarsely toothed; stem hairs sparsely spreading or appressed ..... E. annuus

36' Leaves generally entire; stem hairs appressed ..... E. strigosus var. strigosus

35' Ray flower pappus present; plant taprooted (Erigeron flagellaris generally fibrous-rooted)

37. Stem hairs appressed; plant with herbaceous, leafy runners ..... E. flagellaris

37' Stem hairs spreading; plant without runners ..... E. divergens (3)

34' Perennial herb or subshrub from woody taproot, branched caudex, or rhizome

38. Leaves 1–4-ternately dissected

39. Leaves generally (1)2–3(4)-ternately dissected; ray < 1 mm wide; caudex branches short, thick, ascending ..... E. compositus (2)

39' Leaves deeply 3-lobed at tip; ray 1–2 mm wide; caudex branches thin, rhizome-like ..... E. vagus

38' Leaves entire to shallowly toothed

40. Leaf bases hardened, white-shiny, expanded, enclosing proximal stem

41. Caudex branches thick, leaf bases persistent; rays yellow ..... E. linearis

41' Caudex branches slender, rhizome-like, leaf bases not persistent; rays white, pink to blue or lavender

42. Involucre 13–18 mm diam; basal leaves generally 2–5 mm wide; pappus bristles 25–40; phyllary hairs spreading; >= 2100 m; High Cascade Range, n&c High Sierra Nevada ..... E. barbellulatus

42' Involucre 6–11 mm diam; basal leaves generally 0.5–1 mm wide; pappus bristles 20–30; phyllary hairs appressed; 1000–2200 m; Modoc Plateau ..... E. elegantulus

40' Leaf bases ± thin, not hardened, barely or not expanded

43. Fruit ribs 4–8; herbage generally ± silvery, hairs dense, appressed

44. Fruit ribs 6–8; basal leaves tufted, persistent ..... E. argentatus

44' Fruit ribs 4(6); basal leaves generally 0 at flower

45. Outer pappus conspicuous, of bristles or narrow scales; stem silvery-white ..... E. parishii

45' Outer pappus inconspicuous; stem gray-green, densely strigose ..... E. utahensis

43' Fruit ribs generally 2 (if more, herbage not silvery)

46. Phyllaries strongly graduated; leaves entire, not clasping, basal 0, cauline generally evenly sized and spaced

47. Stem minutely glandular ..... E. aequifolius

47' Stem generally not glandular

48. Stem hairs dense, minutely curled- or bent; fruit glabrous ..... E. blochmaniae

48' Stem hairs 0 to dense, straight, stiffly spreading to ± reflexed or appressed; fruit sparsely strigose

49. Stem hairs dense, stiffly spreading, generally slightly reflexed

50. Herbage hairs 0.5–1 mm; phyllaries densely minutely glandular, inner phyllary tips widely white-thick-margined; stem often from woody basal offsets and roots ..... E. klamathensis

50' Herbage hairs <= 0.1–0.4 mm; phyllaries glandular or glandless, inner phyllary tips green; stem from ± slender, rhizome-like bases ..... E. breweri

51. Phyllaries densely glandular, glandless hairs 0 or very sparse

52. Stem generally >= 20 cm, ascending to erect; leaves generally >= 15 mm ..... var. breweri

52' Stem 7–15 cm, prostrate to decumbent; leaves 5–12 mm ..... var. jacinteus

51' Phyllaries not or barely glandular, glandless hairs prominent

53. Stem 20–30 cm, wiry, brittle; phyllary hairs long, thick-based, stiffly spreading, translucent (also some glandular) ..... var. porphyreticus

53' Stem 30–75 cm, not wiry or brittle; phyllary hairs short, white, ± appressed, glandless

54. Phyllary hairs thin-based, ± appressed, slightly less dense on inner phyllaries ..... var. bisanctus

54' Phyllary hairs thick-based, ascending, much less dense on middle and inner phyllaries ..... var. covillei

49' Stem hairs ± 0 or sparse, appressed

55. Stem prostrate to ± erect, from slender rhizome ..... E. elmeri

55' Stem decumbent to erect, from woody taproot

56. Ray flowers 9–13; leaf ciliate, hairs thin-based; phyllaries with minute glandless hairs and densely minutely glandular ..... E. serpentinus

56' Ray flowers 15–60; leaf ciliate, hairs thick-based; phyllaries glandular or glandless

57. Phyllaries ± glandless, 0.5–0.8 mm wide, margins generally thick to ± scarious

58. Leaves 2–4(5) cm, oriented variously; inner phyllaries 3.2–4.5 mm ..... E. foliosus var. foliosus

58' Leaves (2.5)4–6(8) cm, often ± oriented to 1 side of stem; inner phyllaries (4)5–6 mm

59. Stem 30–85 cm; axillary leaf tufts 0; leaves 35–80 mm, 1–2(4) mm wide; inner phyllaries not strongly scarious; ray flowers 26–50 ..... E. foliosus var. hartwegii

59' Stem 15–28 cm; axillary leaf tufts generally present; leaves 25–45 mm, (2)5–8 mm wide; inner phyllary margins strongly scarious; ray flowers 18–22 ..... E. mariposanus

57' Phyllaries minutely but prominently glandular, 0.8–1 mm wide, margins generally widely scarious ..... E. foliosus (in part)

60. Phyllary hairs all glandular; leaves generally 1–2 mm wide ..... var. confinis

60' Phyllary hairs glandular and glandless, ± densely bristly-strigose; leaves generally 2–4 mm wide

61. Leaf blades ± strigose; phyllary midvein raised, orange-resinous; ray corolla 7–10 mm ..... var. franciscensis

61' Leaf blades ± glabrous (except ciliate hairs); phyllary midvein generally not raised or orange-resinous; ray corolla 10–15 mm ..... var. mendocinus

46' Phyllaries generally ± equal; leaves entire to lobed, sometimes clasping, basal sometimes present, cauline often strongly reduced distally on stem, if present

62. Plant fibrous-rooted, generally from obvious rhizome or ± decumbent caudex; cauline leaves often ± clasping;

63. Glandless phyllary hairs with black cross-walls (sometimes only on basal cells of hairs)

64. Rays white ..... E. coulteri

64' Rays blue to purple ..... E. sanctarum (2)

63' Glandless phyllary hairs 0 or with clear cross-walls

65. Ray flowers 150–400 ..... E. philadelphicus var. philadelphicus

65' Ray flowers 20–165 (80–300+ in E. glaucus)

66. Leaves thick, ± fleshy, entire or toothed; coastal ..... E. glaucus

66' Leaves ± thin, entire; coastal or inland

67. Glandless phyllary hairs prominent, glandular hairs sometimes present

68. Stem from thin, often stolon-like caudex branches with few fibrous roots ..... E. sanctarum (2)

68' Stem from short, thick, strongly fibrous-rooted rhizome or caudex

69. Stem 2–20(30) cm, hairs spreading; phyllaries ± black-purple; pappus bristles 12–16(20) ..... E. algidus (2)

69' Stem 30–100 cm, hairs appressed; phyllaries ± green; pappus bristles 20–30 ..... E. aliceae (2)

67' Glandless phyllary hairs 0, glandular hairs dense

70. Stem glabrous or sparsely minutely glandular; ray flowers 20–30(45) ..... E. cervinus

70' Stem ± appressed-hairy, sometimes also ± bristly; ray flowers 30–105

71. Fruit 2(4)-ribbed, moderately to densely strigose; proximal leaves generally coarsely dentate, sometimes entire ..... E. aliceae (2)

71' Fruit 4–7-ribbed, sparsely strigose; proximal leaves entire ..... E. glacialis

72. Peduncles densely minutely strigose with loosely appressed, slightly crinkled hairs ..... var. glacialis

72' Peduncles bristly or ± stiffly long-soft-hairy ..... var. hirsutus

62' Plant taprooted or with taprooted caudex; cauline leaves not at all clasping

73. Stem spreading- or reflexed-hairy

74. Leaf clearly petioled, blade oblanceolate, elliptic, obovate to spoon-shaped

75. Basal leaves 20–70 mm; cauline leaves much reduced; stem 2–30 cm; phyllaries ± black-purple; ray flowers (30)50–125, ray 7–13 mm ..... E. algidus (2)

75' Basal leaves 5–25 mm; cauline leaves 0; stem 1–4 cm; phyllaries green; ray flowers 15–40, ray 4–6 mm ..... E. uncialis var. uncialis

74' Petiole indistinct, blade linear or oblanceolate, gradually tapered to base

76. Margins of proximal leaves generally hairy but not stiffly spreading-ciliate; generally > 2200 m

77. Basal leaves 20–80 mm; stem sparsely minutely glandular at least distally, and moderately hairy with short, stiffly spreading to reflexed, glandless hairs; phyllaries green; ray flowers 25–55, ray 6–11 mm ..... E. clokeyi var. pinzliae

77' Basal leaves 6–35 mm; stem densely minutely glandular, also with short-stiff and ± spreading glandless hairs; phyllaries ± black-purple; ray flowers 20–37, ray 4–7(10) mm ..... E. pygmaeus

76' Margins of proximal leaves generally stiffly long-spreading-ciliate; 1200–1800 m

78. Disk corolla (±) glabrous; pappus bristles 12–22; outer pappus of inconspicuous bristles or narrow scales; rays (40)55–115, 8–12 mm ..... E. pumilus var. intermedius

78' Disk corolla sharply scabrous; pappus bristles 5–15; outer pappus of prominent wide scales; rays 40–60, 7–9 mm ..... E. concinnus var. concinnus

73' Stem glabrous or ascending- to appressed-hairy (to ± spreading-hairy in Erigeron lassenianus)

79. Ray flowers 75–125; disk corolla throat ± widened ..... E. multiceps

79' Ray flowers generally 14–80; disk corolla ± narrowly cylindric

80. Basal leaves 0 at flower

81. Leaves sharply reduced distally on stem; axillary leaf tufts 0; ray flowers 12–27(45) ..... E. oxyphyllus

81' Only most distal cauline leaves reduced; leaf tufts in axils; ray flowers 45–80 ..... E. karvinskianus

80' Basal leaves generally persistent

82. Basal leaves thread-like to linear

83. Stem 2–8 cm, leafless; stem hairs straight, appressed; basal leaves 5–25 mm; fruit ribs densely ciliate, faces glabrous ..... E. compactus

83' Stem 15–30 cm, generally leafy, at least proximally; stem hairs curved up, ± loose; basal leaves generally 20–70 mm; fruit ribs and faces sparsely hairy ..... E. filifolius

82' Basal leaves narrowly oblanceolate to elliptic or spoon-shaped (or linear in Erigeron lassenianus var. lassenianus and Erigeron robustior)

84. Plants cespitose; caudex stout, branched; basal leaves oblanceolate to elliptic, petioled; cauline leaves abruptly reduced ..... E. tener

84' Plants not cespitose, caudex generally slender; basal leaves linear to narrowly oblanceolate, petiole indistinct; cauline leaves gradually reduced

85. Basal leaves generally persistent; cauline leaves generally smaller than basal; heads 1–4(7) ..... E. eatonii

86. Involucre (14)17–23 mm diam; longest phyllaries 7–11 mm; disk corolla 4.4–6.8 mm ..... var. nevadincola

86' Involucre 8–16 mm diam; longest phyllaries 5–8 mm; disk corolla 3–5 mm

87. Stem 10–23 cm; disk corolla 3–4 mm; pappus bristles 16–20, 3–3.5 mm ..... var. plantagineus

87' Stem 4–12(21) cm; disk corolla 3.5–5 mm; pappus bristles 18–30, 3.5–5 mm ..... var. sonnei

85' Basal leaves persistent at, or withering before, flower; cauline leaves gradually or little reduced; heads (1)2–7(18)

88. Phyllaries densely minutely glandular; involucre 4–5.5 mm, 6–10(12) mm wide; leaves generally 1-veined ..... E. lassenianus var. lassenianus

88' Phyllaries generally glandless; involucre generally 6–8.5 mm, (9)12–20 mm wide; leaves generally 3-veined

89. Plants 10–22(27) cm; taproots ± thick, (3)5–8 mm wide; basal leaves oblanceolate to ± narrowly spoon-shaped; cauline leaves ± continuing to heads; involucres (5)6–7 mm, 9–12(14) mm wide; phyllaries elliptic-oblanceolate to oblong-oblanceolate, abruptly acuminate ..... E. maniopotamicus

89' Plants (15)25–55 cm; taproots ± thin, 2–3 mm wide; basal leaves linear to very narrowly oblanceolate; cauline leaves ending ± well below heads; involucres 6–8.5 mm, (12)14–20 mm wide; phyllaries narrowly oblanceolate to lanceolate, acute-acuminate ..... E. robustior


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Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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