Flora of the Southeastern United States

1 Leaf with (5-) 7-15 leaflets, arranged pedately on a semicircular axis; spadix 9-20 cm long, attenuate, long-exserted from the spathe; [section Flagellarisaema].

  2 Spathe not tightly enclosing the spadix, 2-8 cm broad (when unrolled)/flattened); spathe tube 3-4 cm long; spathe hood 3-4 cm long

  2 Spathe tightly enclosing the spadix, 1-1.5 cm broad when unrolled/flattened); spathe tube 2-3 cm long; spathe hood 2-3 cm long

1 Leaf with 3-5 leaflets, arranged palmately; sterile portion of the spadix 3.5-8 cm long, clavate or cylindrical and blunt, included in the spathe; [section Pistillata].

    3 Spathe hood oriented vertically; sterile spadix strongly clavate, bright white (resembling a porcelain pestle); spathe tube purplish black outside, bright white inside

    3 Spathe hood curved over the orifice of the spathe tube; sterile spadix cylindrical or somewhat clavate, greenish white; spathe tube variously green, white, or purple striped outside and inside.

      4 Leaves pale whitish-green beneath at maturity (this not reliably detectable in herbarium specimens); spathe flange 2-7 mm broad; spathe hood apex acuminate to acute; spathe hood underside green, or green with purple stripes; sterile spadix (appendix) clavate or cylindrical.

        5 Leaves 5-foliolate; sterile spadix 1-2 (-3) mm in diameter, cylindrical, gently curved outward; spathe hood underside green; spathe hood apex abruptly acute; [s. NC and TN south to Panhandle FL, LA, and e. TX]

        5 Leaves 3-foliolate (the 2 lateral leaflets undivided or sometimes lobed, but not fully parted into separate leaflets); sterile spadix (appendix) 3-10 mm in diameter, cylindrical to clavate, straight; spathe hood underside purple, or purple or green striped with white; spathe hood apex acuminate; [collectively widespread in our region]

          6 Sterile spadix 4-7 mm in diameter, clavate; spathe hood purple with greenish-white stripes or green with white stripes, the stripes usually reaching to the apex and weakly anastomosing; spathe flange 5-10 mm wide

          6 Spadix thinner, 3-5 mm in diameter, cylindrical; spathe hood typically purple with one or more white stripes reaching the apex; spathe flange 2-6 mm wide.

             7 Spathe hood length 3-4 cm, purple-black with white stripes reaching above the spadix, but only the median stripe usually reaching the apex; spathe tube length 3-4 cm

             7 Spathe hood length 6-10 cm, purple (less commonly green) with white stripes anastomosing and reaching to the long-acuminate apex; spathe tube length 6-10 cm

      4 Leaves green beneath at maturity (similar in color to the upper surface, but note that this color is not reliably detectable in herbarium specimens); spathe flange 1-5 mm broad; spathe hood apex acuminate to long-acuminate; spathe hood underside green with white stripes, green with purple stripes, solid green, or solid purple; sterile spadix (appendix) cylindrical.

               8 Spathe hood interior green or purple usually without well-defined white stripes; spadix 2-3 mm in diameter; spathe hood apex acuminate

                 9 Lateral leaflets of at least the larger leaf deeply lobed into 2 lobes; spathe hood interior green or suffused with purple in upper part, sometimes with weak striping; spadix 2.5-3 mm in diameter, often bicolored

                 9 Lateral leaflets unlobed or rarely with a lobe much smaller than the main lobe; spathe hood interior usually solid purple or solid green, occasionally with weak white stripes; spadix 2-3 mm in diameter, usually uniformly purple or green

               8 Spathe hood interior green or purple with conspicuous white stripes; spadix 4-6 mm in diameter; spathe hood apex long-acuminate

                   10 Spathe hood not fluted, 6-7 cm long; spathe hood underside green with greenish-white stripes, sometimes suffused with purple