Flora of the Southeastern United States

1 Leaves either mostly in whorls of 3-6 (sometimes some nodes with merely opposite leaves), or subopposite (the leaves more-or-less paired but separated by 0.5-3 mm); corolla whitish, greenish, or creamy yellow, often suffused with rose-purple (especially at the tips of the corolla lobes).

  2 Leaves mostly in whorls of 3-6 (sometimes some nodes with merely opposite leaves); leaves 1.5-3 cm long, 0.5-4 mm wide; seeds 5-8 mm long, the coma ca. 2.5 cm long; milky sap often difficult to show (in living plants).

    3 Stems 1-8 from ground level, typically bearing sterile vegetative branchlets at some nodes at least; leaves glabrous; corona segments with entire margins; [TX and MO westward]

    3 Stems 1 (-3) from ground level, lacking sterile vegetative branchlets; leaves puberulent on the upper surface; corona segments with toothed or lobed margins; [widespread]

  2 Leaves subopposite (the leaves more-or-less paired but separated by 0.5-3 mm); leaves (3-) 5-18 cm long, (1-) 2-10 mm wide; seeds 7-11 mm long, the coma 3-5 cm long; milky sap obvious and profuse (in living plants).

      4 Leaf blades strongly conduplicate (folded lengthwise along the midvein, making a V cross-section).

        5 Stems glabrous; plants 40-170 cm tall; leaves drooping; corollas creamy yellow to greenish or cream colored adaxially, tan to reddish-brown abaxially; hoods with entire apices

        5 Stems puberulent; plants 15-90 cm tall; leaves ascending to spreading; corollas greenish-cream colored on both surfaces; hoods with deeply 2-lobed apices

      4 Leaf blades flat to slightly conduplicate.

          6 Umbel 1, terminal; corona 5-7 mm in diameter; horns present, about as long as the hood; hoods ca. 2-4 mm long, surpassing the anther heads; [dry pinelands of the Coastal Plain]

          6 Umbels 1-4, terminal and from upper nodes; corona 2-3 mm in diameter; horns absent; hoods ca. 2 mm long, surpassed by the anther heads; [either wet pinelands of the Coastal Plain or dry glades or woodlands].

             7 Leaf blades narrowly linear (needlelike); stems 1-13 from ground level, 10-30 cm tall; umbels 3-13 flowered, pedunculate; corolla lobes cream to suffused pink, the lobes reflexed with widely spreading tips; [grasslands in c. OK westward]

             7 Leaf blades linear-lanceolate; stems typically 1-3 from ground level, 25-125 cm tall; umbels 10-100 flowered, sessile or pedunculate; corolla lobes green to whitish or greenish-cream and red-violet at tips, the lobes strongly reflexed with the tips lightly spreading or less commonly strongly spreading [widespread; habitats various].

               8 Pedicels with incurved hairs; umbels 1-6, each with 10-30 flowers; leaves glabrous or nearly so; [wet pinelands of the Coastal Plain]

1 Leaves opposite; corolla white, whitish, or greenish, usually suffused with rose-purple (especially at the tips of the corolla lobes), or creamy yellow, purple, or orange-red.

                 9 Corolla lobes erect (vertical), creamy yellow to dull or greenish white, 7-10 mm long; leaves 2.5-4.5 cm long, puberulent beneath, sessile; plant 1-4 dm tall; [dryish pinelands of the Coastal Plain]

                 9 Corolla lobes reflexed to spreading, either orange-red, with at least some purple, or whitish or greenish, 3-7 mm long (except 8-11 mm long in the orange-red A. lanceolata); leaves (3-) 5-20 cm long, glabrous or glabrate beneath (rarely puberulent), sessile to petiolate; plant 1-15 dm tall; [collectively of various habitats].

                   10 Leaves with petioles 1-10 mm long; leaves 5-15 mm wide; plants 5-15 dm tall.

                     11 Petiole 4-10 mm long; corolla pink (rarely white), the lobes 3-5.5 mm long; hoods 1-2 mm long; horns longer than the hoods; [mostly of the Mountains and Piedmont]

                     11 Petiole 1-3 mm long; corolla orange-red, the lobes 8-11 mm long; hoods 5-6 mm long; horns slightly shorter than the hoods; [of the Coastal Plain]

                   10 Leaves sessile, subsessile (with petioles 0-1 mm long); leaves 1-7 mm wide; plants 1-7 dm tall.

                       12 Leaves 3-7 mm wide.

                          13 Umbel 1, terminal; corona 5-7 mm in diameter; horns present, about as long as the hood; hoods ca. 2-4 mm long, surpassing the anther heads; [dry pinelands]

                          13 Umbels 1-10, terminal and from upper nodes; corona 2-3 mm in diameter; horns absent; hoods ca. 2 mm long, surpassed by the anther heads; [either of wet pinelands of the Coastal Plain or dry glades or woodlands].

                            14 Pedicels with incurved hairs; umbels 1-6, each with 10-30 flowers; leaves glabrous or nearly so; [wet pinelands of the Coastal Plain]

                       12 Leaves 1-2.5 mm wide.

                              15 Pedicels ca. 2 cm long, arching, the flowers often nodding; horns present (somewhat longer than the hood); hoods with 2 erect, acuminate, marginal teeth on the inner side (adjoining the anther heads); corolla ashy-gray, pale violet, or pale rose; [se. NC (historically) and e. SC south to n. peninsular FL, west to s. MS]

                              15 Pedicels 0.6-1.5 cm long, erect to ascending, the flowers facing upwards (or with stiffly erect pedicels but some flowers in the umbel pointed downward in A. linearis); horns absent or present; hoods with or without marginal auricles; corolla white, pale pink, or green (and often suffused with purple); [TX to se. GA and s. AL south to s. FL].

                                16 Upper leaf surfaces puberulent with curved hairs; leaf margins ciliate; stems 1-4, stems often branched; inflorescences 7-20 flowered; corollas cream to brownish, occasionally suffused violet

                                16 Upper leaf surfaces glabrous; leaf margins glabrate to sparsely ciliate; stems 1-2, stems typically solitary (rarely branched near base); inflorescences 2-15 flowered; corollas white, whitish green, or green.

                                  17 Corolla white or pale pink; hoods shorter than the gynostegium; horns absent

                                  17 Corolla green to cream, often suffused with purple; hoods longer than the gynostegium; horns present