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Key to Helianthus, Key D: perennial sunflowers with leafy stems and yellow disk flowers

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1 Stems below the capitulescence glabrous or nearly so, sometimes glaucous.
  2 Leaves whorled at principal nodes, either alternate or opposite at other nodes
  2 Leaves either alternate or opposite (or both), never whorled.
    3 Leaves grayish-green or bluish green in color, sessile, and glabrous and glaucous on the undersurface.
      4 Rays 10-14; leaves strumose adaxially, rough to the touch; phyllaries 3.5-4.5 mm wide
      4 Rays 5-10; leaves glabrous or glabrate adaxially, smooth or only slightly rough to the touch; phyllaries 2-3 mm wide
    3 Leaves light to dark green, sometimes whitish abaxially, but not grayish or bluish green in color; leaves sessile or petiolate, glabrous or pubescent.
        5 Leaves linear-lanceolate, with only a single main vein
          6 Rays few, usually 5 or 8; heads small, the involucres 9 mm broad or less.
             7 Leaves abaxially whitish in color and glabrous and glaucous, lacking subsessile glandular trichomes (‘resin dots’)
             7 Leaves abaxially greenish in color, usually tomentulose (sometimes glabrate), with abundant subsessile glandular trichomes
          6 Rays usually 10 or more in larger heads; heads larger, the involucres usually > 9 mm broad.
               8 Leaves sessile, rounded to cordate at base, and trinerved, with the 2 lateral veins diverging from the midrib at the very base of the leaf
               8 Leaves sessile to petiolate, but narrowing gradually to base and triplinerved, the 2 lateral veins diverging from the midrib above the base of the blade.
                   10 Leave blade lanceolate to lance-ovate, sessile to petiolate but the petiole usually < ¼ as long as the blade; phyllaries not conspicuously graduated and imbricate, usually loose and spreading
                   10 Leaf blade ovate to elliptic, with a distinct petiole usually > 2 cm long and ½ as long as blade or longer; phyllaries conspicuously graduated and imbricate, usually appressed, not exceeding disk
                 9 Anther appendages dark or reddish-brown.
                     11 Plants producing abundant tubers; leaves subsessile, the petioles < 1 cm long; [endemic to the Piedmont of NC and SC]
                     11 Plants rhizomatous, but not producing tubers; leaves petiolate, the petioles 1-5 cm long; [collectively widespread in our area].
                       12 Longer phyllaries usually exceeding disk by ½ their length or more, apex acuminate; larger leaves moderately to conspicuously serrate, with a petiole 2-5 cm long, and abaxially with usually relatively few subsessile glandular trichomes
                       12 Phyllaries equal to or slightly exceeding disk, apex acute; leaves moderately serrate to entire, with a petiole 1-3 cm long, and abaxially with usually abundant subsessile glandular trichomes (‘resin dots’)
1 Stems pubescent throughout, not glaucous.
                          13 Leaves petiolate or sessile, but not cordate, and alternate or opposite.
                            14 Phyllaries attenuate, conspicuously exceeding the disk in length and reflexed, apically with numerous subsessile glandular trichomes (‘resin dots’); leaf bases often convex, the basically ovate or lance-ovate blade joined to a broadly winged and gradually narrowed petiole
                            14 Phyllaries acute to attenuate, but not reflexed, subsessile glandular trichomes present or absent; leaf bases usually attenuate to truncate or rounded, the blade lance-linear or lanceolate, or if ovate or lance-ovate either sessile or with a petiole that is at most narrowly winged.
                              15 Leaves conduplicate (strongly folded along the midvein, thus V-shaped) and entire, usually with only a single prominent main vein; inflorescence when well developed spiciform or racemose
                                  17 Leaf blades lanceolate to ovate, petiole 1-5 cm long and usually < ½ as long as blade; anther appendages with dark pigment; cypselas 4-5 mm, usually sterile
                                  17 Leaf blades ovate to elliptic, petiole distinct, > 2 cm and usually > ½ as long as the blade; anther appendages yellow; cypselas 3-4 mm long, fertile
                                16 Phyllaries not conspicuously graduated and imbricate, usually loose or spreading.
                                       19 Leaves with a prominent petiole > 2 cm long, blades lance-ovate to ovate and > 5 cm broad; cypselas 5-7 mm long; tubers produced late in growing season
                                       19 Leaves sessile or with a short petiole usually < 2 cm long; blades linear to lanceolate, < 4.5 cm broad; cypselas 3-5 cm long; tubers present or absent.
                                           21 Ligules abaxially with subsessile glandular trichomes (‘resin dots’); leaves usually revolute.
                                             22 Heads relatively small, the discs usually < 15 mm across; tubers present
                                             22 Heads larger, the discs (at least the larger) > 15 mm across; tubers absent.
                                               23 Leaves conspicuously undulate; ovate to elliptical to lanceolate, occasionally linear (if so, usually < 10 cm long), usually < 5× as long as wide; heads 1-6 per plant; outer phyllaries acute to obtuse
                                               23 Leaves not conspicuously undulate; linear to lanceolate, > 5× as long as broad (and also 8-16 cm long); heads 3-16 per plant; outer phyllaries acuminate to acute.
                                                 24 Plants short, < 1.5 m tall; leaves < 1 cm wide; rhizomes lacking or poorly developed
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