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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 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 paleate
               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

Key to Asteraceae, old Key J: Herbaceous composites with the leaves alternate or basal and the heads radiate, the rays white, pink, purple

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1 Receptacles chaffy (paleate).
  2 Phyllaries dry, scarious-margined.
    3 Ray florets 1-5 mm long; heads small in corymbiform arrays
    3 Ray florets > 5 mm long; heads large, terminating the branches
  2 Phyllaries herbaceous, not scarious on margins.
      4 Ray florets < 2.5 mm long; disk florets sterile, with an undivided style
      4 Ray florets > 5 mm long; disk florets fertile, with a divided style.
        5 Ray florets pink or light purple, > 15 mm long; heads single
        5 Ray florets white, 5-10 mm long; heads 20-100 in a compound corymb
1 Receptacles naked (epaleate).
          6 Pappus absent or coroniform.
             7 Achene faces minutely glandular-glochidiate (bearing small gland-like bristles)
             7 Achene faces glabrous or short-strigose but not glandular-glochidiate.
               8 Leaves basal; cypselae marginally 2-ribbed; mature plants < 2 dm tall
               8 Leaves cauline (and sometimes also basal); cypselae with ± 10 ribs; mature plants > 2 dm tall
                 9 Heads solitary or 2-3 in corymbiform arrays
                 9 Heads 5-60+ in corymbiform arrays
          6 Pappus present, of bristles or scales.
                   10 Heads radiate with conspicuous ray florets.
                     11 Taprooted annuals; ray florets 1-7 mm long.
                       12 Leaves and stems not fleshy, rarely glabrous; cypselas < 1.4 mm long
                       12 Leaves and stems fleshy, mostly glabrous; cypselas > 1.4 mm long
                     11 Not taprooted and mostly perennials; ray florets > 3 mm long.
                          13 Ray florets usually > 60; blooming Apr-Oct
                          13 Ray florets usually < 60; blooming late May-Nov.
                            14 Receptacles hemispheric to conic; pappus often with 2-4 awns (Boltonia) or lacking awns and coroniform (Astranthium).
                              15 Achenes not narrowly winged, the surfaces minutely glandular-glochidiate (bearing small gland-like bristles)
                              15 Achenes narrowly winged, the surfaces sometimes puberulent but not glandular-glochidiate
                            14 Receptacles flat to slightly convex; pappus lacking awns.
                                16 At least the basal and lower leaves both petiolate and cordate/subcordate at base.
                                  17 Often colonial; inflorescence corymbiform, flat-topped or rounded; outer phyllaries > 1 mm broad
                                  17 Not colonial; inflorescence paniculiform, often elongate; outer phyllaries < 1 mm broad
                                16 Basal and lower leaves not both petiolate and cordate/subcordate at base.
                                    18 Leaves sessile and auriculate or cordate-clasping
                                    18 Leaves petiolate or epetiolate but not auriculate or cordate-clasping.
                                       19 Cypselas glandular; pappus double
                                       19 Cypselas not glandular; pappus single or double or in four series.
                                         20 Leaves silvery-silky on both sides (at least when young), entire
                                         20 Leaves not silvery-silky, entire or toothed.
                                           21 Pappus double, with inner bristles distinctly longer than outer bristles.
                                             22 Leaves not rigid, veiny, lanceolate to elliptic or ovate, > 6 mm wide
                                             22 Leaves rigid, 1-nerved, linear to linear-spatulate, < 5 mm wide
                                           21 Pappus simple with all bristles often about the same length.
                                               23 Ray florets white, few (usually 3-8); cypselas densely silky
                                               23 Ray florets white to pink or blue or purple, more numerous (usually 8-30); cypselas glabrous to pubescent but not densely silky.
                                                 24 Ray florets white; involucres < 6 mm long; phyllaries < 1 mm wide
                                                 24 Ray florets white or pink to blue or purple; involucres 7-12 mm long; phyllaries usually > 1 mm wide.
                                                    25 Phyllaries glandular
                                                    25 Phyllaries not glandular.
                                                      26 Phyllaries long-attenuate or loose and spreading
                                                      26 Phyllaries appressed, not long-attenuate.
                                                        27 Plants coarse-hairy; lowest leaves > 5 cm wide
                                                        27 Plants glabrous to hairy; lowest leaves < 3 cm wide