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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 B: annual sunflowers

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1 Disk flowers yellow.
  2 Leaves ovate, 10-40 cm long, 5-25 cm wide, toothed, the base often cordate or subcordate; disc corollas 5-8 mm long; stems 10-30 dm tall; [section Helianthus]
  2 Leaves lanceolate, 5-10 cm long, 0.2-1.0 cm wide, entire or nearly so, the base cuneate; disc corollas 2.8-3.5 mm long; stems 4-10 dm tall; [section Porteri]
1 Disk flowers red or purple (at least in part).
    3 Leaves, stems, and phyllaries densely covered with soft, silvery-white pubescence; [section Helianthus]
    3 Leaves, stems, and phyllaries nearly glabrous to scabrous or hirsute.
      4 Style branches yellow; [section Agrestes]
      4 Style branches red; [section Helianthus].
        5 Phyllaries ovate to ovate-oblong, > 4 mm wide; leaves 5-25 cm wide; disk (2-) 3-30 cm wide; plants (0.5-) 1-3 m tall
        5 Phyllaries lanceolate, 1-4 (-5) mm wide; leaves 1.5-9 cm wide; disk 1-2.5 cm wide; plants 0.4-1.5 m tall.
          6 Tips of the receptacular bracts (paleae) in the center of the head conspicuously white-bearded.
             7 Leaves mostly alternate; petioles 5-9 cm long; ray flowers 10-30; [widely distributed in our region, native and adventive]
             7 Leaves mostly opposite; petioles 2-4 cm long; ray flowers 11-13; [TX coastal prairies and s. TX]
          6 Tips of the receptacular bracts (paleae) in the center of the head not bearded.
               8 Leaves mostly opposite; phyllaries 30-39, short acuminate at tip; [TX]
               8 Leaves mostly alternate; phyllaries 20-30, acute to long-attenuate at tip; [collectively widespread in our region].
                 9 Stems decumbent, with ascending or erect flowering branches; peduncles 9-20 (-22) cm long; blades of the ray flowers 11-16 mm long; [of FL peninsula].
                   10 Stems glabrous or puberulent; leaves serrulate to evenly serrate; [of east coast of FL peninsula, from St. Johns County south to Monroe County)]
                   10 Stems hirsute-villous; leaves deeply and irregularly coarsely serrate; [of west coast of FL peninsula, from Hernando County south to Lee County]
                 9 Stems erect; peduncles 10-50 cm long; blades of the ray flowers 14-30 mm long; [collectively widespread in our region].
                     11 Leaves 8-14 cm long; peduncles 20-40 cm long; discs 10-15 (-17) mm in diameter; [w. LA and e. TX]
                     11 Leaves 2.5-9 cm long; peduncles 10-50 cm long; discs 14-20 mm diam; [collectively widespread in our region].
                       12 Peduncles 25-50 cm long; leaves usually shallowly but regularly serrate; ligules usually > 2 cm long; blades of the ray flowers (15-) 20-30 mm long
                       12 Peduncles usually 10-25 (-30) cm long; leaf usually deeply and irregularly coarsely serrate; ligules usually < 2 cm long; blades of the ray flowers 12-20 (-22) mm long
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