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Keyed in multiple places:

Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

Key to Asteraceae, Key M: Herbaceous composites with the leaves alternate or basal and the heads radiate, the rays white, pink, purple, and with a pappus of bristles only

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1 Head 1 per plant (individual rosette); stems 0.1-0.3 dm tall; [TX and OK westwards]
1 Heads 5-300+ per (well-developed) plant; stems 0.3-35 dm tall; [collectively widespread].
  2 Stems with numerous thorns (1-2 cm long, modified axillary branches), and few or no leaves
  2 Stems leafy, not armed with thorns.
    3 Leaves pinnatifid to bipinnatifid; plant annual
    3 Leaves unlobed; plant perennial from caudices, crowns, or rhizomes.
      4 Annuals from taproots; ray florets 0.3-7 mm long.
        5 Ray laminae 0.3-1.0 mm long; cypselas 1.0-1.5 mm long, compressed, 1-nerved on each face
        5 Ray laminae 1.3-7 mm long; cypselas (1.2-) 1.5-2.7 (-3) mm long, compressed or not, 5-18-nerved.
          6 Disc flowers 25-35 per head; ray flowers in 1 series
          6 Disc flowers 4-10 (-13) per head; ray flowers in 1-3 series
      4 Perennials from caudices, crowns, or rhizomes; ray florets > 3 mm long.
             7 Basal and lower stem leaves petiolate, with blades cordate to rounded at the base
               8 Heads borne in corymbiform arrays, the branches often subtended by large and leaf-like bracts; phyllaries < 2.5 (-3)× as long as wide, often > 1 mm wide; plants (in most species) colonial by rhizomes; rays (in most species) white; phyllaries (in many species) glandular
               8 Heads borne in paniculiform arrays, the branches bearing small and narrow bracts; phyllaries > 3× as long as wide, often < 1 mm wide; plants (in most species) solitary; rays (in most species) blue, violet, or pink; phyllaries eglandular
             7 Basal and lower stem leaves sessile (sometimes cordate-clasping), or if petiolate then with cuneate to attenuate bases.
                 9 Rays pink, purple, lavender, blue, or pale pink [plants with pale pink rays may need to be keyed both ways].
                   10 Heads borne in paniculiform or in diffuse and irregular arrays
                   10 Heads borne either in flat-topped or rounded, corymbose arrays, or in narrow racemiform or spiciform panicles, or solitary.
                     11 Leaves 1.2-4.0 cm long, 1-4 mm wide, stiff, scabrous margined and weakly spine-tipped; plants 1-7 dm tall; pappus in 2 series, the inner much longer than the outer (ca. 1 mm long) bristles
                     11 Leaves either longer or broader or both, herbaceous; Leaves (5-) 13-45 mm wide, herbaceous, neither scabrous-margined nor spine-tipped; plants 4-30 dm tall; pappus not divided into distinct inner and outer series.
                       12 Plants 10-35 dm tall; larger leaves (basal or low on the stem) with cuneate or attenuate bases, the blades 30-50 cm long; [non-native, rarely persistent or spreading from horticultural use]
                       12 Plants 1-12 dm tall; larger leaves with blades 2-20 cm long; [natives, collectively widespread and common in our region]
                 9 Rays white (or very slightly pink-flushed).
                          13 Heads borne in paniculiform or in diffuse and irregular arrays
                          13 Heads borne either in flat-topped or rounded, corymbose arrays, or in narrow racemiform/spiciform panicles, or solitary.
                            14 Heads arrayed in 1 (or more) cylindrical thyrses
                            14 Heads borne in either narrow racemiform/spiciform panicles, or in corymbose arrays.
                              15 Heads borne in narrow racemiform/spiciform panicles
                              15 Heads borne in corymbose arrays.
                                16 Disc flowers yellow (and often fading to pink or purplish).
                                  17 Rays 2-7, the ray ligules 2-11 mm long, often twisted or contorted; phyllaries whitish with a distinct green tip, the green area about as wide as long
                                  17 Rays (8-) 9-40, the ray ligules 4-20 mm long, generally planar (or neatly coiling at post-maturity); phyllaries various.
                                    18 Pappus double, with an outer set of bristles < 1 mm long; leaves entire
                                    18 Pappus not divided into distinctively different outer and inner series; leaves toothed or entire.
                                       19 Achenes not glandular, either glabrous or strigillose
                                       19 Achenes densely gland-dotted

Key to Solidago, Key G: Key to "ptarmicoid goldenrods" -- with corymbs [subgenus Pleiactila, section Ptarmicoidei]

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1 Rays white; leaves linear-lanceolate to linear-oblanceolate, the longer (10-) 15-20× as long as wide; pappus bristles slightly to strongly clavellate-thickened;
1 Rays yellow; leaves oblong, elliptic, obovate, or spatulate, 2-8× as long as wide; pappus bristles not clavellate thickened.
  2 Leaves of the midstem 1-7 mm wide, 10-20× as long as wide; ray flowers 1-4/head, disk flowers 7-13/head; [AR, OK, MS, LA, and TX]
  2 Leaves of the midstem 8-20 mm wide, 2-12× as long as wide; ray flowers 6-14/head; disk flowers 6-35/head; [collectively widespread].
    3 Leaves of the midstem 8-12 mm wide, 4-12× as long as wide; leaf surfaces, stems, and peduncles glabrous; [marshes, swamps, moist to wet prairies, of OH, IN, OL, MO, and AR (allegedly disjunct in nw. GA and e. VA].
      4 Leaves essentially planar, with only the midvein prominent; leaves straight to slightly curved, appressed to ascending
      4 Leaves folded along the midvein (conduplicate, V-shaped in ×-section), with 3-7 veins prominent from the base of the blade; stem leaves strongly recurved away from the stem
    3 Leaves of the midstem 12-20 mm wide, 2-3.5× as long as wide; leaf surfaces, stems, and peduncles glabrescent to densely pubescent; dry to moist prairies, glades, and savannas].
        5 Outer series of phyllaries glabrous on the back (glabrous to short-ciliate on the margin); leaf undersurface glabrous to somewhat hispid (0-20 hairs per square mm) (the margins and midrib beneath often more densely pubescent); stems glabrous to somewhat hispid (0-25 hairs per square mm)
        5 Outer series of phyllaries pubescent on the back (short-ciliate on the margin); leaf undersurface hispid (7-50 hairs per square mm); stems slightly to strongly hispid (10-70 hairs per square mm).
          6 Pubescence of the stems and leaf surfaces finely and densely hispid-strigose, > 50 hairs per square mm; plants usually 3-7 dm tall; flowering arrays compact; inner phyllaries linear, conspicuously strigillose
          6 Pubescence of the stems and leaf surfaces coarsely hispid, < 50 hairs per square mm; plants 6-15 dm tall; flowering arrays loose, more diffuse; inner phyllaries oblong and with a rounded apex, glabrate or sparsely strigillose
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