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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 Helianthus, Key A: sunflowers with basally disposed leaves

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1 Disk flowers yellow.
  2 Basal leaves 6-15 cm long, 2-8 cm wide; leaves 1.5-5× as long as wide, scabrous or hirsute (rarely glabrous)
    3 Leaves rough to touch, scabrous or hirsute; leaves entire or nearly so; [widely distributed]
    3 Leaves smooth to touch, strigose or glabrous; leaves usually serrate; [AR, LA, TX]
  2 Basal leaves 10-30 cm long, 0.5-2.0 cm wide; leaves 10-20× as long as wide, glabrous.
      4 Head 1 (-3); phyllaries 8-16 mm long, 3-5 mm wide; [of wet flatwoods and wet prairies of ne. FL]
      4 Heads 3-12; phyllaries 5-11 mm long, 1-2.5 mm wide; flowering Aug-Oct; [of sandstone and granite glades and woodlands and loamy to xeric longleaf pine sandhills; rarely escaped elsewhere]
1 Disk flowers red or purple (at least in part).
        5 Basal leaves 6-20 cm long; lower several pairs of stem leaves up to 1/2 as long and wide as the basal leaves; [collectively widespread in our region from VA, KY, IL, MO, and OK southwards, in the inland provinces and the Coastal Plain].
          6 Trichomes on the leaf abaxial midrib > 1 mm long; lower stem with a few pairs of leaves (< 8 nodes below the capitulescence), these strongly reduced upward; leaf blades (1.3-) 1.7-2.5 (-3)× as long as wide; petiole often > 1/3 as long as the blade, broadly winged toward the blade; plants to 2 m tall; nonflowering stems usually absent; [widespread in our area]
          6 Trichomes on the leaf abaxial midrib < 1 mm long; lower stem leafy, often to above the middle (> 8 nodes below the capitulescence); leaf blades 1-1.7 (-2)× as long as wide; petiole usually < 1/3 as long as the blade, narrowly winged toward the blade; plants to 3 m tall; nonflowering stems usually present; [west of our area]
        5 Basal leaves 4-15 cm long; lower several pairs of stem leaves often < 1/2 as long and wide as the basal leaves; [Coastal Plain, NC to FL to e. LA].
             7 Basal leaves (1.6-) 2-5× as long as wide; ray flowers present, 12-18, typically 1.5-3.5 cm long; [wet savannas and bogs]
             7 Basal leaves 1-1.5× as long as wide; ray flowers none, or present, 2-8, but < 1 cm long; [dry savannas and sandhills]