1 Plant a prostrate herb, usually not twining, with stems 0.2-0.6 (-1.1 m) long at maturity; leaf blades 2-4 (-6) cm long; cymes sessile; flowers (2-) 3-4 (-5) per inflorescence; upper (inner) surface of the petals pubescent; [xeric sandhills, from e. GA southward]

1 Plant a twining herbaceous vine, with stems 1-2 m long at maturity; leaf blades 7-27 cm long; cymes borne on peduncles; flowers (2-) 9-19 (-53) per inflorescence, except M. alabamensis, with (1-) 4-5) (-12) flowers per inflorescence; upper (inner) surface of the petals glabrous; [various habitats, but more mesic, collectively widespread in our area].

  2 Inflorescence with 1-12 flowers, averaging 4-5; corolla light green, reticulated with darker green; corona disc-shaped, smooth or with obscure ridges (lacking 5 pairs of appendages); [mesic slopes of s. GA, Panhandle FL, and s. AL]

  2 Inflorescence with 2-53 flowers, averaging 9-19; corolla white, yellow, rose, or maroon (or greenish and reticulate in M. flavidula); corona cup-shaped, either 5-lobed (each with 4 teeth) (M. floridana), or 10-lobed with 5 short broad lobes alternating with 5 narrower 2-toothed lobes; [collectively widespread].

    3 Corona 5 lobed, each lobe with 4 teeth; corolla lobes ca. 5 mm long; [endemic to FL and sw. GA]

    3 Corona 10-lobed (5 short broad lobes alternating with 5 narrower 2-toothed lobes); corolla lobes 6-15 mm long; [collectively widespread].

      4 Corolla lobes in a horizontal plane or reflexed; flower buds ovoid to broadly conical, < 1.5× as long as wide; corolla lobes 1.5-5× as long as wide.

        5 Corolla dark maroon (rarely maroon-yellow or yellow), not reticulate with darker veins; paired corona appendages always higher than the alternating corona lobes

        5 Corolla green, green-yellow, or yellow (rarely rosy or olive-maroon), reticulate with darker green veins; paired corona appendages about as high as the alternating corona lobes

      4 Corolla lobes ascending; flower buds conical, > 2× as long as wide; corolla lobes 2.4-6.2× as long as wide.

          6 Corolla white (or fading or drying cream); corona 2.2-2.7 mm in diameter, cream or creamy-yellow; [Panhandle FL and sw. GA westward]

          6 Corolla rose or maroon (rarely cream); corona 2.6-4.0 mm in diameter, rose to dark maroon (rarely green, cream, or orange); [primarily Mountains and Piedmont].

             7 Corolla lobes (3.2-) 4.0-6.2× as long as wide, the widest part at the sinus; corolla rose to light maroon (rarely dark maroon, green, or cream)