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Key to Pediomelum

Fabaceae

Pediomelum

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1 Leaves pinnately 3-foliolate; plant a prostrate or ascending vine; corolla orange, red, or bronze; [w. AR and w. LA westward]; [subgenus Leucocraspedon]
1 Leaves palmately (1-) 3-7-foliolate; plant a caulescent or acaulescent herb; corolla blue, lavender, or purple to cream or white; [collectively widespread].
  2 Plants acaulescent or nearly so, the aboveground stem 0-2 cm long; leaves (3-) 5-7-foliolate; corollas 11-18 mm long.
    3 Upper calyx lobes ca. 1 mm long, much shorter than the calyx tube; leaflets 5-7; [calcareous glades of the Interior (nw. GA, TN, n. AL)]
    3 Upper calyx lobes 5-8 mm long, longer than or about the same length as the calyx tube; leaflets (3-) 5; [sw. AR and w. LA westward].
      4 Peduncles 1.0-3.5 cm long, < 1/2 as long as the subtending petiole; [wc. OK and nc. TX westwards and northwestwards]
      4 Peduncles (1.7-) 4-14 cm long, > 1/2 as long as the subtending petiole.
        5 Peduncles and petioles appressed-pubescent; leaflets 2.5-6.0× as long as wide, mostly less than 10 mm wide; [Edwards Plateau and western edge of the TX Coastal Plain]
        5 Peduncles and petioles spreading pilose; leaflets 1.7-3.0× as long as wide, mostly 10-30 mm wide; [sw. AR and w. LA west through e. OK and e. TX]
  2 Plants caulescent, 3-10 dm tall; leaves (1-) 3-7-foliolate; corollas 5-25 mm long.
          6 Flowering calyx 1.5-2.5 mm long, the legume (ca. 8 mm long) obviously exserted out of it at maturity; corolla 5-7 mm long; [IN, KY, and MS westward]; [former genus Psoralidium]
          6 Flowering calyx 7-10 mm long, the legume mostly included within it even at maturity (only the beak sometimes projecting); corolla 7-25 mm long.
             7 Leaflets > (8-) 10× as long as wide; [OK and TX westward].
               8 Corollas 12-18 mm long; calyx 8-10 mm (when in flower), enlarging to as much as 15 mm in fruit
               8 Corollas 9-11 mm long; calyx 4.5-5.5 mm long (when in flower), only slightly enlarging in fruit
             7 Leaflets 1-8× as long as wide; [collectively widespread].
                 9 Leaves (1-) 3 (-4)-foliolate, the largest leaves on a plant 3 (-4)-foliolate; petioles of midstem leaves < 1 cm long; plants repeatedly and divaricately branched, “bushy”.
                   10 Leaflets 1.0-1.8× as long as wide; petiolules 5-9 mm long; calyx ca. 7 mm long (when in flower), elongating to ca. 10 mm (in fruit); [se. VA south to c. peninsular FL, west to AL]
                   10 Leaflets 2.0-4.0× as long as wide; petiolules 1.5-3 mm long; calyx 11-16 mm long; [SC and GA (P. piedmontanum) or OK and TX (P. reverchonii)].
                     11 Inflorescence nodes (4-) 6-13 (-15), each with (1-) 3 (-4) flowers; [lower Piedmont of SC and GA]
                     11 Inflorescence nodes 2-3, each with 1-3 flowers; [Cross Timbers and Prairies region of sc. OK and nc. TX]
                 9 Leaves 3-7-foliolate, at least the larger leaves on a plant 5- or 7-foliolate; petioles of midstem leaves (0.2-) 2-8 cm long; plants either repeatedly and divaricately branched, or less branched or unbranched.
                       12 Inflorescences with 2-7 flower clusters well spaced from one another; plant divaricately branched, bushy; corollas 7-11 mm long; leaflets 2-8× as long as wide
                          13 Leaflets 2-4.5× as long as wide; herbs silvery sericeous; pedicels 0.5-1 mm long; [nc. OK westwards]
                          13 Leaflets 4-8× as long as wide; herbs strigose or appressed canescent to glabrate, not silvery; pedicels 1-3 mm long; sw. AR, nw. LA, e. and nc. TX, and c. OK, westwards]
                       12 Inflorescences not interrupted; plant strict (unbranched) or moderately branched; corollas 14-25 mm long; leaflets 2-5 (-6)× as long as wide.
                            14 Plants eglandular (lacking sessile glands on stems, foliage, etc.); stems 0.3-5 dm tall; [e. OK, n. AR, and s. MO northward and westward]
                            14 Plants glandular; [e. OK and e. TX westward].
                              15 Larger stipules < 2.5 mm wide
                              15 Larger stipules 2.5-7 mm wide.
                                16 Stem hairs appressed
                                16 Stem hairs spreading