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See list of 7 species in this genus

Reference: Bogler (2006a).

  • 1a. Cypselas of 2 kinds—those borne near the margin of the capitulum stout, 7–9 mm long, with a short beak and those from the interior of the capitulum slender, 12–17 mm long, and with a long, slender beak
  • 1b. Cypselas ± uniform, 1.4–7.5 mm long
    • 2a. Inner series of involucral bracts glabrous on the adaxial (i.e., inner) surface; cypsela body 1.4–2.5 mm long (up to 4 mm long in the rarely collected C. nicaeensis)
    • 2b. Inner series of involucral bracts pubescent on the adaxial (i.e., inner) surface; cypsela body (2.5–) 3–8 (–9) mm long
      • 4a. Capitula with 10–20 florets; involucral bracts coarsely hispid abaxially; cypsela tapered to a short beak 1–2 mm long
      • 4b. Capitula with 30–100 florets; involucral bracts tomentose to hispidulous abaxially, sometimes also with stipitate glands in C. vesicaria; cypsela narrowed to summit of ovary and without a beak or with a prominent beak 2–5 mm long
        • 5a. Cypsela with a slender beak 2–5 mm long; outer involucral bracts (i.e., the smaller ones) reflexed at maturity, sometimes with stipitate glands on the abaxial surface; abaxial surface of rays red
        • 5b. Cypsela narrowed to summit of ovary but without a beak; outer involucral bracts spreading-ascending to erect, usually without stipitate glands on the abaxial surface; rays entirely yellow
          • 6a. Involucre (8–) 10–13 mm tall; cypsela body 4–7.5 mm long, yellow to red-brown, with (10–) 13–20 smooth, longitudinal ribs; pappus 5–7 mm long; stem leaf blades oblanceolate or oblong to spatulate, with plane margins
          • 6b. Involucre 6–9 mm tall; cypsela body (2.5–) 3–4 (–4.5) mm long, red to purple-brown, with 10 minutely scabrous, longitudinal ribs; pappus 4–5 mm long; stem leaf blades linear to lanceolate or oblanceolate, with revolute margins

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