1. Plants usually glabrous or glabrate (at most arachnose to tomentose at bases of stems, in axils of leaves, and/or at bases of heads); basal leaves usually entire or dentate, seldom pinnately lobed, pinnatifid, or pinnatisect | → 2 |
1. Plants usually tomentose, sometimes glabrous, glabrate, or glabrescent and/or basal leaves pinnately lobed, pinnatifid, or pinnatisect | → 32 |
2. Plants 3–20(–30+) cm; heads usually 1–6+; arctic or alpine to subalpine | → 3 |
2. Plants 20–100 cm; heads (2–)6–20(–100+); relatively low latitudes to arctic, never alpine | → 11 |
3. Heads (1–)3–6+; ray florets 0 or 8–13 (corolla laminae 6–10+ mm); calyculi conspicuous or inconspicuous (bractlets with swollen bases or cyanic only at tips) | → 4 |
3. Heads 1–2(–5+); ray florets 0 or 10–13 (corolla laminae 7–14 mm); calyculi conspicuous (bractlets usually deeply cyanic to purple-tinged) | → 6 |
4. Cauline leaves gradually reduced (mid and distal sometimes as large as or larger than basal, usually clasping, sometimes auriculate) | P. dimorphophylla |
4. Cauline leaves abruptly reduced (clasping or not, not auriculate) | → 5 |
5. Basal leaves (relatively thick and turgid) elliptic-ovate or suborbiculate to spatulate; peduncles ebracteate, glabrous; calyculi inconspicuous | P. malmstenii |
5. Basal leaves (not thick or turgid) ovate, oblanceolate, or spatulate; peduncles bracteate, lanate-tomentose; calyculi conspicuous | P. hesperia |
6. Basal leaves: blades reniform to subreniform, bases abruptly contracted to cordate, margins crenate or wavy | → 7 |
6. Basal leaves: blades mostly ovate, obovate, oblanceolate, or spatulate, sometimes elliptic, lyrate, or reniform, bases usually tapering to cuneate, sometimes contracted, margins subentire to crenate-dentate, dentate, or weakly lobed to pinnatifid | → 8 |
7. Plants 3–10 cm (rhizomes 5–15+ cm, slender); stems glabrous; disc florets 40–50+ | P. porteri |
7. Plants 6–25+ cm (rhizomes 1–6 cm, branched, stout); stems glabrous but for bases and leaf axils; disc florets 60–75+ | P. cymbalaria |
8. Cypselae hirtellous on ribs | P. hyperborealis |
| → 9 |
9. Cauline leaves abruptly reduced (lanceolate, weakly clasping, entire or dentate); disc florets 40–55+ | P. subnuda |
9. Cauline leaves gradually or abruptly reduced (lanceolate to linear, not clasping, usually pinnatisect or pinnately lobed, rarely entire); disc florets 55–75+ | → 10 |
10. Basal leaves (relatively thick, fleshy): blades usually ovate, oblong, or spatulate, sometimes lyrate; cauline leaves gradually reduced; phyllaries white-tomentose proximally; cypselae 1–1.25 mm | P. contermina |
10. Basal leaves (not notably thick or fleshy): blades ovate to obovate, lyrate, or reniform; cauline leaves abruptly reduced; phyllaries glabrous; cypselae 1.5–2 mm | P. cymbalaria |
11. Basal leaves (relatively thick and turgid; herbage glaucous) | P. clevelandii |
11. Basal leaves (rarely thick and/or turgid; herbage glabrous or tomentose, not glaucous) | → 12 |
12. Ray florets 0 or 8–13 (corolla laminae 2–7 mm) | → 13 |
12. Ray florets 0 or 5–21 (corolla laminae 4–12+ mm) | → 15 |
13. Cauline leaves gradually reduced (pinnately lobed, sinuses relatively deep, round); heads in corymbiform arrays; pappi 4.5–5.5 mm | P. debilis |
13. Cauline leaves gradually or abruptly reduced (subentire to shallowly pinnatifid); heads in subumbelliform arrays; pappi 3–4.5 mm | → 14 |
14. Basal leaves (relatively thick and turgid); heads 1–6+; peduncles bracteate (bractlets cyanic or reddish); phyllaries deep red or green (then tips deep red to purple) | P. pauciflora |
14. Basal leaves (relatively thin, flaccid); heads 8–20+; peduncles usually ebracteate; phyllaries green with cyanic tips | P. indecora |
15. Basal leaves (and proximal cauline): bases abruptly contracted or truncate to strongly cordate or subcordate | → 16 |
15. Basal leaves (and cauline): bases gradually tapering (sometimes obtuse) | → 24 |
16. Basal leaves: blades broadly to narrowly lanceolate, narrowly ovate, or subhastate, margins serrate-dentate or sharply dentate (apices acute) | → 17 |
16. Basal leaves: blades cordate, obovate, orbiculate, ovate, or reniform, margins crenate, dentate, lobed, or wavy (apices rounded) | → 18 |
17. Basal leaves: blades broadly lanceolate to subhastate; heads in subumbelliform arrays; calyculi inconspicuous; disc florets 70–80+;w of Mississippi River | P. pseudaurea |
17. Basal leaves: blades narrowly ovate to oblong-lanceolate; heads in loose, corymbiform arrays; calyculi conspicuous; disc florets 50–70+; e of Mississippi River | P. schweinitziana |
18. Basal leaves: blades cordate or reniform | → 19 |
18. Basal leaves: blades orbiculate, orbiculate-ovate, or obovate | → 21 |
19. Basal leaves: margins sharply dentate to shallowly lobed; phyllaries dark green with yellow margins (plants fibrous-rooted, not rhizomatous) | P. ganderi |
19. Basal leaves: margins crenate, irregularly dentate, wavy, or lobed; phyllaries light green or green with purple or black tips (plants rhizomatous) | → 20 |
20. Cauline leaves abruptly reduced (sometimes clasping, irregularly dentate or crenate); heads 3–8; calyculiconspicuous; phyllaries light green | P. cardamine |
20. Cauline leaves gradually reduced (not clasping, lobed, lateral lobes 2–4 pairs); heads 6–20+; calyculi inconspicuous; phyllaries green (tips purple or black) | P. aurea |
21. Stems glabrous or sparsely hairy (at bases); peduncles ebracteate or inconspicuously bracteate, glabrous; calyculi 0 or inconspicuous | → 22 |
21. Stems tomentose (at bases and in leaf axils); peduncles conspicuously bracteate, glabrous or sparsely tomentose; calyculi conspicuous | → 23 |
22. Disc florets 40–60+; cypselae 5–6 mm | P. ganderi |
22. Disc florets 60–80+; cypselae 1–1.5 mm | P. crocata |
23. Plants stoloniferous; cauline leaves gradually reduced (clasping, margins pinnatisect or pinnately lobed) | P. obovata |
23. Plants fibrous-rooted; cauline leaves gradually to abruptly reduced (not clasping, margins entire or subentire) | P. streptanthifolia |
24. Basal leaves (and proximal cauline): blades obovate, orbiculate, ovate, or suborbiculate (lengths usually 1–2 times widths) | → 25 |
24. Basal leaves (and proximal cauline): blades elliptic, elliptic-ovate, lanceolate, lyrate, oblanceolate, orbiculate, ovate, or spatulate (lengths usually 2–3 times widths) | → 27 |
25. Basal leaves: margins deeply dissected or pinnatifid to pinnately lobed; cauline leaves abruptly reduced (stems subscapiform); phyllaries light green with yellow tips; disc florets 20–30+ (plants rhizomatous) | P. flettii |
25. Basal leaves: margins crenate, dentate, or serrate; cauline leaves gradually reduced; phyllaries green or reddish; disc florets 40–65+ (plants fibrous-rooted, sometimes stoloniferous) | → 26 |
26. Stems and leaf axils usually glabrous, sometimes tomentose proximally; heads 8–15+; peduncles conspicuously bracteate, glabrous or proximally tomentose; calyculi conspicuous | P. obovata |
26. Stems and leaf axils usually floccose-tomentose, sometimes glabrate; heads 3–9+; peduncles inconspicuously bracteate, loosely tomentose or glabrescent;calyculi 0 | P. hartiana |
27. Heads 20–70(–100+); disc corolla tubes 1.5–2 mm, limbs 1.5–2 mm; cypselae 0.75–1 mm | P. anonyma |
27. Heads 2–20+; disc corolla tubes 2–5.5 mm, limbs 2–5 mm; cypselae 1–2.5 mm | → 28 |
28. Plants taprooted (caudices woody) | → 29 |
28. Plants fibrous-rooted, rhizomatous, or taprooted (caudices not woody) | → 30 |
29. Basal leaves (and proximal cauline): blades lanceolate or narrowly oblanceolate, margins entire, subentire, or dentate (distally); calyculi conspicuous; phyllaries 6–10 mm, tomentose proximally; cypselae 1.5–2.5 mm | P. tridenticulata |
29. Basal leaves (and proximal cauline): blades elliptic-ovate, broadly oblanceolate, or lyrate, margins irregularly and deeply pinnately parted or lobed; calyculi usually 0, sometimes inconspicuous; phyllaries 4–6+ mm, glabrous; cypselae 1–1.5 mm | P. texensis |
30. Basal leaves (relatively thick and turgid): blades oblanceolate, orbiculate, ovate, or spatulate; cauline leaves gradually or abruptly reduced (entire or subentire); calyculi conspicuous; disc florets 35–60+ | P. streptanthifolia |
30. Basal leaves (relatively thin, not turgid): blades lanceolate to narrowly elliptic; cauline leaves gradually reduced (margins dissected, incised, lacerate, or lobed); calyculi 0 or inconspicuous; disc florets 50–80+ | → 31 |
31. Plants ± rhizomatous (rhizomes weakly branched); stems glabrous or sparsely tomentose proximally; cauline leaves gradually reduced (sessile, dissected, incised, or lacerate); ray corolla laminae (pale yellow) 5–18+ mm | P. paupercula |
31. Plants fibrous-rooted; stems glabrous; cauline leaves gradually reduced (sessile, weakly clasping, ± lobed, often sublyrate); ray corolla laminae (deep yellow to orange-red) 6–8+ mm | P. crocata |
32. Basal (and cauline) leaves usually pinnately lobed, pinnatifid, or pinnatisect (herbage usually glabrous or glabrate, sometimes persistently tomentose) | → 33 |
32. Basal leaves usually entire or ± dentate, or pinnately lobed (herbage usually tomentose or glabrescent) | → 55 |
33. Ray florets 0 or 1 (corolla laminae ca. 6 mm) | → 34 |
33. Ray florets (rarely 0) 5–13 (corolla laminae 3–15+ mm) | → 35 |
34. Plants 5–10 cm; stems densely white- or gray-tomentose; basal leaves: blades oblanceolate (pinnatifid), 20–30+ × 5–13+ mm, ultimate margins crenate | P. musiniensis |
34. Plants 20–50+ cm; stems sparsely tomentose (mostly bases and leaf axils); basal leaves: blades elliptic to ovate or subreniform, 20–40+ × 15–30+ mm, margins subentire to crenate-dentate | P. debilis |
35. Stems (and leaves) usually (persistently) tomentose, sometimes glabrescent | → 36 |
35. Stems (and leaves) usually glabrous, sometimes tomentose (mostly bases and leaf axils) | → 44 |
36. Basal leaves (and proximal cauline): blades narrowly elliptic, lanceolate, lyrate, oblanceolate, or sublyrate | → 37 |
36. Basal leaves (and proximal cauline): blades broadly elliptic, obovate, orbiculate, ovate, or spatulate | → 40 |
37. Plants 3–20 cm; heads 1–6; phyllaries purple or with purple streaks | → 38 |
37. Plants 20–60+ cm; heads 6–25+; phyllaries green (tips sometimes red) | → 39 |
38. Stems (not branched) sparsely lanate or tomentose; basal leaves: margins pinnately lobed (lyrate to sublyrate, midribs winged); Arizona | P. franciscana |
38. Stems (usually branched distally) sparsely to densely floccose-tomentose; basal leaves: margins irregularly to pinnately lobed; Yukon; Alaska. | P. ogotorukensis |
39. Stems (and leaves) tomentose (throughout); basal leaves: margins evenly pinnatifid or pinnatisect; ray florets 6–8 (corolla laminae 5–7 mm); disc florets 30–40+; cypselae glabrous | P. fendleri |
39. Stems densely tomentose (at bases, otherwise sparsely tomentose); basal leaves (abaxial faces sometimes sparsely hairy): margins pinnately lobed (sublyrate) to irregularly pinnatisect; ray florets 8–10 (corolla laminae 9–10 mm); disc florets 60–70+; cypselae hirtellous on ribs | P. plattensis |
40. Plants taprooted (caudices becoming branched); basal leaves: margins pinnately lobed | → 41 |
40. Plants rhizomatous or fibrous-rooted; basal leaves: margins pinnatifid to irregularly lobed | → 42 |
41. Plants 30–50 cm; basal leaves (early withering): margins pinnately lobed (lateral lobes 2–6+ pairs, terminal lobes coarsely serrate or finely dissected), ultimate margins irregularly and coarsely serrate-dentate or finely dissected | P. eurycephala |
41. Plants 15–30 cm; basal leaves: margins pinnately lobed (lateral lobes 1–3 pairs, smaller than terminals), ultimate margins entire or subentire to crenate or wavy | P. ionophylla |
42. Plants 3–8 cm (stems purplish); phyllaries cyanic (Arizona) | P. franciscana |
42. Plants 8–60+ cm (stems green); phyllaries green (tips sometimes cyanic) | → 43 |
43. Plants 8–15+ cm (often branched distally); heads 1(–3); Yukon; Alaska | P. ogotorukensis |
43. Plants 20–60+ cm (not branched); heads 6–20+ (in corymbiform arrays); s Canada; c United States | P. plattensis |
| → 45 |
44. Plants rhizomatous or fibrous-rooted | → 49 |
45. Basal leaves: margins pinnately lobed (lateral lobes 6+ pairs or lobing irregular, terminal lobes smaller than laterals) | → 46 |
45. Basal leaves: margins pinnately lobed (lateral lobes 1–6+ pairs, terminal lobes larger than laterals) | → 47 |
46. Basal leaves: blades narrowly lanceolate; peduncles inconspicuously bracteate or ebracteate; calyculi inconspicuous; pappi 3.5–4.5 mm; e of Continental Divide | P. millelobata |
46. Basal leaves: blades obovate, oblanceolate, or spatulate; peduncles bracteate; calyculi conspicuous; pappi 5–6 mm; w of Continental Divide | P. multilobata |
47. Plants 60–100+ cm (stems deeply purple-tinged at bases, lightly tinged distally); basal leaves: blades pinnately lobed (bases of lateral lobes relatively wide, midribs weakly winged), ultimate margins sharply dentate or irregularly incised | P. quercetorum |
47. Plants 20–50 cm (stems sometimes red-tinged at bases); basal leaves: blades pinnately lobed (bases of lateral lobes petioluliform, midribs sometimes winged or toothed), ultimate margins crenate to crenate-dentate | → 48 |
48. Annuals (stems reddish at bases); cauline leaves gradually reduced (often auriculate); peduncles bracteate; disc florets 30–45(–100+); wet, sandy or clay sites, stream banks, waste areas | P. tampicana |
48. Perennials (stems green); cauline leaves gradually to abruptly reduced (not auriculate); peduncles ebracteate; disc florets 60–75+; limestone plateaus, granitic sands along roadsides, oak woodlands | P. texensis |
49. Basal leaves: margins 2–3 times pinnately dissected | P. millefolium |
49. Basal leaves: margins mostly pinnatifid or pinnately lobed | → 50 |
50. Plants 20–70+ cm (stems striated, often hollow, pink to purple tinged) | P. glabella |
50. Plants 6–100+ cm (stems not striated or hollow) | → 51 |
51. Plants 6–20 cm; heads 1–2(–5); cypselae hirtellous on ribs (n coastal Alaska, North West Territories, Banks Island, and Yukon) | P. hyperborealis |
51. Plants 20–100+ cm; heads 3–50+; cypselae glabrous | → 52 |
52. Plants 40–100+ cm; basal leaves: blades spatulate to obovate (pinnately lobed, lateral lobes 2–6+ pairs, smaller than terminals), ultimate margins dentate to lacerate; heads 15–50+; disc florets 45–60+; dry, rocky soils, oak savannahs | P. breweri |
52. Plants 10–50 cm; basal leaves: blades cordate, oblanceolate, obovate, ovate, or subcordate (pinnately lobed or incised, lateral lobes 1–3 pairs, equaling terminals), ultimate margins crenate to dentate; heads 4–15+; disc florets 20–50+; damp, rocky soils, streambeds, meadows | → 53 |
53. Basal leaves: blades broadly oblanceolate (pinnately lobed, bases of terminal and lateral lobes petioluliform, midribs not winged); New Mexico | P. sanguisorboides |
53. Basal leaves: blades cordate to subcordate or obovate to ovate (pinnately lobed, bases of terminal and lateral lobes not contracted, sinuses rounded, midribs winged); Oregon, Washington | → 54 |
54. Basal leaves: blades cordate to subcordate; cauline leaves gradually reduced distally (petiolate); heads 8–15+; phyllaries dark green; disc florets 30–45+ | P. bolanderi |
54. Basal leaves: blades obovate to ovate; cauline leaves abruptly reduced distally (sessile, stems scapiform); heads 4–10+; phyllaries light green (tips yellowish); disc florets 20–30+ | P. flettii |
55. Plants 3–10 cm; heads 1–6(–15+) | → 56 |
55. Plants 10–50+ cm; heads (1–)6–30+ | → 64 |
56. Ray florets 0 or 1–8 (corolla laminae 4–7 mm) | → 57 |
56. Ray florets (0) 8–13+ (corolla laminae 4–16 mm) | → 59 |
57. Basal leaves sessile, blades linear, margins entire (strongly revolute) | P. spellenbergii |
57. Basal leaves ± petiolate, blades obovate to oblanceolate or spatulate, margins entire, crenate, or pinnatifid | → 58 |
58. Basal leaves: margins entire or crenate; phyllaries purple-tinged, tomentose (apices with dense tufts of hairs) | P. castoreus |
58. Basal leaves: (blades often pinnatifid) ultimate margins crenate; phyllaries yellow-green to purple (or with purplish midstripes), sparsely tomentose (apices rounded) | P. musiniensis |
59. Stems (often branched proximally, sometimes distally), sparsely tomentose to densely floccose-tomentose; British Columbia, Yukon; Alaska | P. ogotorukensis |
59. Stems (not branched) lanate or canescent, or glabrous, glabrescent, or sparsely tomentose; not Arctic | → 60 |
60. Plants ± rhizomatous (rhizomes branched); stems canescent, floccose-tomentose, lanate, or lanate-tomentose | → 61 |
60. Plants fibrous-rooted (caudices slender) or rhizomatous (rhizomes creeping); stems glabrous, glabrate, arachno-tomentose, sparsely lanate, or sparsely tomentose (then sometimes glabrescent) | → 62 |
61. Cauline leaves gradually reduced (blades similar to basals); cypselae 2.5–3.5 mm | P. cana |
61. Cauline leaves abruptly reduced (bractlike); cypselae 1.5–2 mm | P. werneriifolia |
62. Basal leaves: blades lyrate to sublyrate (pinnately lobed, midribs winged) or ovate to orbiculate and margins ± dentate; cauline leaves gradually reduced | P. franciscana |
62. Basal leaves: blades oblanceolate, ovate, or spatulate, margins entire, subentire, or dentate (toward apices); cauline leaves abruptly reduced (stems often scapiform) | → 63 |
63. Peduncles inconspicuously bracteate, glabrous or densely hairy; calyculi conspicuous (bractlets often cyanic); Rocky Mountains, through Nevada to California (at or above timberline) | P. werneriifolia |
63. Peduncles conspicuously bracteate, densely lanate-tomentose; calyculi inconspicuous (bractlets red-tinged); s Oregon | P. hesperia |
64. Plants taprooted (caudices often branched) | → 65 |
64. Plants fibrous-rooted or rhizomatous | → 68 |
65. Basal leaves: blades lanceolate or oblanceolate, margins entire or shallowly dentate (slightly revolute) | P. macounii |
65. Basal leaves: blades lyrate (pinnately lobed), obovate, broadly ovate, or spatulate, ultimate margins dentate, denticulate, dissected, pinnatifid, subentire, or subserrate | → 66 |
66. Basal leaves: blades ovate to lanceolate or narrowly lanceolate, margins subentire or denticulate to subserrate (abaxial faces often cyanic, usually tomentose, adaxial faces often glabrate) | P. neomexicana |
66. Basal leaves: blades often lyrate (pinnately lobed), ultimate margins crenate to irregularly and coarsely dentate (at least toward apices) or pinnatifid (abaxial faces not cyanic, sparsely to densely tomentose) | → 67 |
67. Plants 20–50+ cm; taprooted (caudices branched, ascending to erect, woody); basal leaves (soon withering): blades obovate, ovate, or spatulate (sometimes pinnately lobed to pinnatifid, lateral lobes 2–6+ pairs), ultimate margins irregularly and coarsely dentate | P. eurycephala |
67. Plants 15–30+ cm; taprooted (caudices not woody) or rhizomatous (rhizomes branched); basal leaves (persistent): blades ovate, sometimes lyrate (often pinnately lobed, lateral lobes 1–3 pairs), ultimate margins crenate to coarsely dentate (at least toward apices) | P. ionophylla |
68. Heads 1–5; ray corolla laminae 8–16 mm | → 69 |
68. Heads (2–)5–30+; ray corolla laminae 5–10(–16) mm | → 70 |
69. Basal leaves: blades orbiculate to ovate or rhombic, margins irregularly dentate; ray florets 8–10 (corollas red-orange, laminae 8–15 mm) | P. greenei |
69. Basal leaves: blades narrowly elliptic or lanceolate to oblanceolate, margins entire, subentire, or weakly dentate; ray florets 5 or 8 (corollas yellow, laminae 12–16mm) | Packera layneae |
70. Stems single (not from rosettes) | → 71 |
70. Stems single (each from a rosette, rosettes usually in clusters of 2–5+) | → 72 |
71. Stems lanate to floccose-tomentose; cauline leaves gradually reduced; heads 10–30+; disc florets 50–60+; pappi 5–7 mm | P. tomentosa |
71. Stems tomentose; cauline leaves abruptly reduced; heads 6–12+; disc florets 25–35+; pappi 4–5 mm | P. antennariifolia |
72. Basal leaves: blades usually broadly oblanceolate to spatulate, sometimes lanceolate to elliptic (then cypselae 1–1.5 mm and hirtellous on ribs) | → 73 |
72. Basal leaves: blades elliptic, lanceolate, oblanceolate, or obovate (not spatulate) | → 75 |
73. Stems densely lanate to glabrescent; heads in compact, cymiform arrays; calyculi 0; cypselae 0.75–1 mm | P. bernardina |
73. Stems sparsely floccose-tomentose, tomentose, or glabrate; heads in corymbiform or subumbelliform arrays; calyculi conspicuous or inconspicuous; cypselae 1–2.5 mm | → 74 |
74. Stems tomentose; calyculi inconspicuous; phyllaries densely tomentose; cypselae hirtellous on ribs | P. antennariifolia |
74. Stems usually glabrous, sometimes floccose-tomentose proximally and in leaf axils; calyculi conspicuous; phyllaries glabrous; cypselae glabrous | P. streptanthifolia |
75. Basal leaves (relatively leathery, or thick and turgid): blades narrowly elliptic to lanceolate or oblanceolate, margins entire, subentire, or wavy | → 76 |
75. Basal leaves (not leathery, nor thick and turgid): blades elliptic, oblanceolate, orbiculate, ovate, or sublyrate, margins entire, crenate, dentate, serrate, pinnately lobed, or pinnatisect | → 78 |
76. Cauline leaves (relatively leathery) gradually reduced (proximals and mids nearly as large as basals); heads 10–30+ in open or congested, cymiform arrays; peduncles 0 or ebracteate, densely tomentose (usually relatively short) | P. cynthioides |
76. Cauline leaves (relatively thick and turgid, not leathery) abruptly or gradually reduced; heads 4–15+ in open, corymbiform, cymiform, or subumbelliform arrays; peduncles bracteate, sparsely tomentose or glabrate | → 77 |
77. Phyllaries dark green proximally, light green distally, floccose-tomentose; ray corolla laminae 12–16 mm; cypselae 2.5–3.5 mm | P. layneae in part) |
77. Phyllaries green (tips sometimes cyanic), glabrous; ray corollalaminae 5–10 mm; cypselae 1–2.5 mm | P. streptanthifolia |
78. Basal leaves: blades orbiculate to broadly ovate | → 79 |
78. Basal leaves: blades narrowly elliptic, narrowly ovate, or oblanceolate | → 80 |
79. Basal leaves: margins entire, weakly crenate, dentate, or lobed; phyllaries glabrous; cypselae glabrous | P. streptanthifolia |
79. Basal leaves: margins dentate to pinnatisect; phyllaries densely tomentose proximally; cypselae usually hirtellous, sometimes glabrous | P. plattensis |
80. Basal leaves: margins crenate or serrate-dentate to pinnately lobed, pinnatifid, or pinnatisect | → 81 |
80. Basal leaves: margins entire, subentire, or dentate (toward apices) | → 82 |
81. Plants rhizomatous and/or fibrous-rooted, sometimes stoloniferous (mostly eastern populations); basal leaves: margins dentate or pinnately lobed to pinnatisect; disc florets 60–70+; cypselae usually hirtellous, sometimes glabrous; pappi 6.5–7.5 mm | P. plattensis |
81. Plants rhizomatous (rhizomes branched, plants not fibrous-rooted or stoloniferous); basal leaves: margins wavy or evenly pinnatifid to pinnatisect; disc florets 30–40+; cypselae glabrous; pappi 4–5 mm | P. fendleri |
82. Stems densely lanate-tomentose or canescent; calyculi inconspicuous; cypselae glabrous | P. cana |
82. Stems lanate- or arachno-tomentose or glabrescent; calyculi conspicuous; cypselae usually hirtellous on ribs, sometimes glabrous | P. neomexicana |