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Erigeron

See list of 7 species in this genus

Phylogenetic work by Noyes (2000) has altered the circumscription of the genus Erigeron 
 as treated by some recent authors. Both Conyza and Trimorpha have been shown to 
be nested within Erigeron. Therefore, these genera are here subsumed under Erigeron. 
Reference: Nesom (2006a).

  • 1a. Involucre 5–12 mm tall; peduncles with glandular hairs; capitula with a series of rayless, carpellate flowers within the series of ray flowers; pappus elongating in fruit and conspicuously surpassing the involcure
  • 1b. Involucre 2–7 mm tall; peduncles without glandular hairs; capitula with carpellate ray flowers and bisexual disk flowers; pappus not or scarcely elongating in fruit, not or only somewhat exceeding the involucre
    • 2a. Rays 0.5–1 (–2) mm long [Fig. 400]; involucre 2–5 mm wide (sometimes wider in pressed specimens); disk 1–3 (–4) mm wide in life
    • 2b. Rays 4–10 mm long (very rarely wanting) [Fig. 401]; involucre 5–20 mm wide; disk (3–) 5–20 mm wide in life
      • 3a. Leaves linear to linear-oblanceolate, 1–5 mm wide; stems tufted and bearing axillary, sterile, leafy branches [Fig. 401]; capitula with 20–50 ray flowers [Fig. 401]; capitula numbering 1–4 (–5) per stem, often solitary
      • 3b. Leaves linear to suborbicular, 2.5–70 mm wide; stems not tufted, usually without sterile, axillary branches; capitula with 50–400 ray flowers; capitula numbering 3–30 (–100) per stem (only 1–4 (–5) in E. pulchellus)
        • 4a. Stem leaves gradually tapering to the base; pappus of 2 types—the inner of long, slender bristles, the outer of short scales; pappus of ray flowers shorter than 1 mm
          • 5a. Principal stem leaves linear to lanceolate, entire or subentire, mostly 2.5–10 (–15) mm wide; pubescence of mid-stem 0.1– 0.4 (–0.8) mm long, usually ascending to appressed (longer and more spreading in var. septentrionalis); rays 4–6 mm long; basal leaf blades often persistent through flowering
          • 5b. Principal stem leaves broad-lanceolate to ovate, toothed, mostly 10–35 (–70) mm wide; pubescence of mid-stem 0.5–1.2 mm long, spreading; rays 4–10 mm long; basal leaf blades often withering prior to flowering
        • 4b. Stem leaves rounded to clasping at the base; pappus of 1 type—long, slender bristles; pappus of all the flowers much longer than 1 mm
          • 6a. Capitula with 50–100 ray flowers, the rays 0.8–1.7 mm wide; disk corollas (4–) 4.5–6 mm long; body of cypsela 1.3–1.8 mm long; plants with slender, elongate, superficial rhizomes; capitula numbering 1–4 (–5) per stem
          • 6b. Capitula with 150–400 ray flowers, the rays up to 0.5 mm wide; disk corollas (2.1–) 2.5–3.2 mm long; body of cypsela 0.6–1.1 mm long; plants without superficial rhizomes; capitula numbering 3–30 (–40) per stem

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 Show photos of:   Each photo represents one species in this genus.