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.

Click images to enlarge and show more photo credit.

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

Apocynaceae

Asclepias

Copy permalink to share | Check for keys that lead to this key

1 Leaves subopposite
1 Leaves opposite (or apparently whorled in A. quadrifolia).
    3 Follicle pendant; seeds without a coma; [of swamp forests of SC and southward]
    3 Follicle erect; seeds with a coma; [collectively widespread].
      4 Leaf-bearing nodes 3-4, the upper and lower opposite, the middle with a whorl of 4 leaves
      4 Leaf-bearing nodes 3-many, all opposite.
        5 Follicle slightly to strongly muricate
          6 Leaf blades lanceolate to ovate or oblong, 2-14 cm wide; petioles tomentose to pilose; follicle apex long-acuminate; [MO, TX, & c. OK westward]
             7 Lower leaf surface glabrous, or pubescent on the midrib only.
               8 Leaves 3-11 cm wide; leaf blades broadly ovate to oblong or elliptic; follicles 12-14 cm long
               8 Leaves 0.5-3 cm wide; leaf blades elliptic, ovate, lanceolate or linear; follicles 6-13 cm long.
                 9 Stems pilosulous in a line or glabrate; leaf blades elliptic or oval to linear; follicles 6-10 mm long; [widespread exotic in disturbed areas]
                 9 Stems puberulent in a line; leaf blades ovate to lanceolate or elliptic; follicles 9-13 mm long; [native in canyons, moist woods, and hillsides in c. & w. TX southward]
                   10 Leaves lanceolate to lance-ovate, 4-10× as long as wide.
                     11 Leaves coriaceous, 3-10 cm long, 1.5-4.5 cm wide; [of dry upland situations]
                     11 Leaves herbaceous, 6-15 cm long, 2-7 cm wide; [of moist to wetland or dry situations].
                       12 Plants 0.6-3 dm tall; petioles puberulent; follicles lance-ovoid; coma 2.5-3.5 cm long; [dry habitats of c. and s. TX southward]
                       12 Plants 3-15 dm tall; petioles pilosulous to pilose; follicles fusiform; coma 1.5-2 cm long; [widespread in moist to wet habitats].
                          13 Stems and leaves sparsely pubescent to glabrescent; leaves narrow, the base obtuse to truncate, the apex long-acuminate; plants usually much branched
                          13 Stems and leaves moderately to densely pubescent; leaves broader, the base rounded to subcordate, the apex acute to short-acuminate; plants usually relatively strict
                   10 Leaves ovate to elliptic, 1.5-4× as long as wide.
                            14 Stem moderately to densely pubescent; plants 1.5-5 (-7) dm tall; [of xeric pinelands and plains of the Coastal Plain of from NC to s. FL, west to OK, AR, and TX].
                                16 Leaf bases rounded, truncate, or subcordate; leaf surfaces tomentose to glabrate; follicles pilosulous; plants 2-10 dm tall
                            14 Stem glabrous to pubescent in lines only; plants 2-12 dm tall; [collectively of various habitats throughout our area].
                                    18 Lower leaf surface glabrous or slightly pubescent; [of moist or dry habitats].
                                         20 Leaves with subcordate, truncate, or broadly rounded bases; [ne. FL to s. peninsular FL]
                                         20 Leaves with cuneate or rounded bases; [widespread in our area, but not ne. FL and peninsular FL]