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Key to Asteraceae, Key I: Herbaceous composites with the leaves alternate, the heads lacking rays, and with a pappus wholly or partly of scales or awns

Asteraceae

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1 Disc flowers yellow, orange, red, or brownish.
  2 Leaves 1-2× pinnately lobed into linear or filiform segments.
    3 Pappus of 16-20 scales
    3 Pappus of 6-10 scales; [historical waif]
  2 Leaves unlobed, or if pinnately lobed, the segments broad (> 3 mm wide).
      4 Receptacle paleate
      4 Receptacle epaleate.
        5 Pappus scales rudimentary, crown-like
        5 Pappus scales conspicuous.
          6 Phyllaries 25-125 in 3-9 series; receptacles flat or slightly convex
          6 Phyllaries 6-25 (-60) in 2-3 series; receptacles globose.
             7 Stems not winged
             7 Stems winged from node to node
1 Disc flowers pink, purple, or white
               8 Receptacle epaleate.
                 9 Disc flowers 1-5 (rarely more) per head.
                   10 Disc flowers white (rarely cream), 3; heads not aggregated into a secondary cluster subtended by bracts; [se. TX]
                   10 Disc flowers lavender to purple, sometimes so lightly so as to be white, 1-4 (-5+); heads aggregated into clusters of 1-40 heads, subtended by 1-3 bracts; [collectively widespread in our region]
                     11 Heads (1-) 10-40 per secondary cluster, borne in corymbiform arrays; bracts subtending clusters (2-) 3, deltate; pappus of 5 (-6) scales, each aristate
                     11 Heads 1-5+ per secondary cluster, borne in spiciform arrays; bracts subtending clusters 1-2, linear, lanceolate, or spatulate; pappus of 6-10 scales, laciniate or aristate
                 9 Disc flowers (2-) 10-100+ per head (at least most heads with >10 flowers).
                       12 Phyllaries 5-15 (-21) in 1-2 (-3) series.
                          13 Involucres 2-3 mm in diameter; flowers 7-10 per head; [Coastal Plain, FL and GA]
                          13 Involucres 4-15+ mm in diameter; flowers 20-80 per head; [SC, GA, and FL westwards]
                       12 Phyllaries 18-many in 5+ series.
                            14 Phyllary tips modified into a spine or into an enlarged, lacerate or pectinate network or fringe; receptacle epaleate, but densely bristly; [tribe Cynareae].
                              15 Heads discoid, all flowers similar
                                16 Pappus normally of plumose bristles (and keyed elsewhere), but sometimes reduced to scales or awns
                                16 Pappus of an outer setiform scales (appearing as "flattened bristles"
                              15 Heads disciform or radiant, the outer flowers of the head sterile, with long lobes, appearing like false rays
                                  17 Plant a perennial; flowers pink to purple, flowering Jun-Oct
                                  17 Plant an annual; flowers pale to medium blue, flowering Apr-Jun
                            14 Phyllary tips not so modified, unarmed and unelaborate; receptacle epaleate and naked; [tribe Vernonieae].
                                    18 Peripheral flowers of the heads enlarged and bilaterally symmetrical, appearing like "false rays"
                                    18 Peripheral flowers of the heads similar to the interior flowers, all disc flowers.
                                       19 Annuals; cypselas not ribbed
                                       19 Perennials; cypselas 8-10-ribbed.
                                         20 Heads each subtended by 3-8 leafy bracts; pappus of narrow scales only, quickly falling
                                         20 Heads not subtended by leafy bracts; pappus of an inner series of scales or bristles and an outer series of bristles, persistent