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Key to Asclepias, Key D: milkweeds with milky sap, with petiolate, nonlinear leaves, in flower

Apocynaceae

Asclepias

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1 Corolla (not the corona) greenish, either pale green or yellowish green.
  2 Leaves subopposite (to alternate upwards); corolla lobes 7-17 mm long.
    3 Corolla lobes 7-12 mm long; leaves mostly 4-7× as long as wide, acuminate at the apex; [e. OK and e. TX and westwards]
    3 Corolla lobes 13-17 mm long; leaves mostly 2-4× as long as wide, obtuse at the apex; [c. TX and c. OK and eastwards]
  2 Leaves opposite; corolla lobes 6-10 mm long.
      4 Corona 2-3 mm across; corolla lobes pale green, 5-7 mm long; [of various provinces, Coastal Plain and also especially inland]
        5 Corolla lobes reflexed-rotate; corona white to pink, with purple markings; [ne. FL to s. peninsular FL]
        5 Corolla lobes strongly reflexed, appressed to the pedicel; corona green, white, or yellowish, with purple markings; [widespread in our area, but not ne. FL and peninsular FL]
      4 Corona 5-9 mm across; corolla lobes yellowish green, 9-10 mm long; [strictly of the Coastal Plain, of NC and SC, and southward].
          6 Hoods ca. 6 mm long, about 2× as long as the gynostegium; stem and leaves densely tomentulose
          6 Hoods ca. 4 mm long, scarcely exceeding the gynostegium; stem and leaves softly puberulent
1 Corolla (NOT the corona) pink, purple, crimson, orange, or white.
             7 Hoods about as long as the anther heads; horns 1-2× as long as the hood, exserted slightly to well beyond the hood.
               8 Hood opening truncate, the hood therefore beaker-shaped; corolla lobes 8-12 mm long; [primarily of mesic forests of the Mountains]
               8 Hood opening very oblique, the hood therefore scoop-shaped; corolla lobes 2.5-10 mm long; [primarily of wetlands of various provinces].
                 9 Corolla bright orangey red, the lobes 5-10 mm long; corona orangey yellow; gynostegium orangey yellow
                 9 Corolla white, pink, rose, or purple, the lobes 2.5-6 mm long; corona white, pink, or rose; gynostegium white or pale pink.
                   10 Plants 3-5 dm tall; corolla lobes usually white (rarely slightly pink); corona white; leaves glabrous beneath; [of the Coastal Plain of SC]
                   10 Plants 5-15 dm tall; corolla lobes rose to purple (rarely white); corona pink or rose; leaves pubescent to glabrate beneath; [collectively widespread].
                     11 Stems and leaves sparsely pubescent to glabrescent; leaves narrow, the base obtuse to truncate, the apex long-acuminate; plants usually much branched
                     11 Stems and leaves moderately to densely pubescent; leaves broader, the base rounded to subcordate, the apex acute to short-acuminate; plants usually relatively strict
             7 Hoods distinctly longer than the anther heads; horns 0.5-1× as long as the hood, not conspicuously exserted beyond the hood.
                       12 Lower leaf surface pubescent over the surface.
                          13 Hood margin irregular but not with a sharp tooth; umbels terminal and extra-axillary; corolla purplish-rose; leaves with 1-2 stipular colleters on each side of petioles, abaxial surfaces sparsely pilosulous; plants 4-10 dm tall
                          13 Hood margin with a single, ascending, triangular tooth; ; leaves with 1-5 stipular colleters on each side of petioles, abaxial surfaces tomentose to glabrate; corolla rose or greenish-white; plants (5-) 8-20 dm tall
                       12 Lower leaf surface glabrous to sparsely pubescent along the midvein only.
                            14 Hood opening very oblique, the hood therefore scoop-shaped, and also with 2 prominent lateral teeth; corolla pink to greenish (rarely white); plants 2-5 dm tall
                            14 Hood opening truncate and constricted, and lacking prominent teeth; corolla white (often pink at the "waist"); plants 3-12 dm tall

Key to Asclepias, Key E: milkweeds with milky sap, with petiolate, nonlinear leaves, in fruit (or sterile)

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1 Leaves subopposite
1 Leaves opposite (or apparently whorled in A. quadrifolia).
  2 Follicle pendant; seeds without a coma; [of swamp forests of SC and southward]
  2 Follicle erect; seeds with a coma; [collectively widespread].
    3 Leaf-bearing nodes 3-4, the upper and lower opposite, the middle with a whorl of 4 leaves
    3 Leaf-bearing nodes 3-many, all opposite.
        5 Lower leaf surface glabrous, or pubescent on the midrib only
          6 Leaves 1-3 cm wide; follicles 6-10 cm long
          6 Leaves 3-11 cm wide; follicles 12-14 cm long
        5 Lower leaf surface pubescent.
             7 Leaves lanceolate, 4-10× as long as wide.
               8 Leaves coriaceous, 3-10 cm long, 1.5-4.5 cm wide; [of dry upland situations]
               8 Leaves herbaceous, 6-15 cm long, 2-7 cm wide; [of moist to wetland situations].
                 9 Stems and leaves sparsely pubescent to glabrescent; leaves narrow, the base obtuse to truncate, the apex long-acuminate; plants usually much branched
                 9 Stems and leaves moderately to densely pubescent; leaves broader, the base rounded to subcordate, the apex acute to short-acuminate; plants usually relatively strict
             7 Leaves ovate to elliptic, 1.5-4× as long as wide.
                   10 Stem moderately to densely pubescent; plants 1.5-5 (-7) dm tall; [of xeric pinelands of the Coastal Plain of from NC to s. FL, west to OK, AR, and TX].
                   10 Stem glabrous to pubescent in lines only; plants 2-12 dm tall; [collectively of various habitats throughout our area].
                       12 Lower leaf surface densely puberulent; [primarily of moist to wet habitats]
                       12 Lower leaf surface glabrous or slightly pubescent; [of moist or dry habitats].
                            14 Leaves with subcordate, truncate, or broadly rounded bases; [ne. FL to s. peninsular FL]
                            14 Leaves with cuneate or rounded bases; [widespread in our area, but not ne. FL and peninsular FL]