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Key to Fabaceae, Key K: herbaceous legumes with pinnately trifoliolate leaves [subfamily Faboideae]

Fabaceae

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1 Leaflets denticulate (sometimes inconspicuously so); [tribe Trifolieae].
  2 Inflorescences elongate racemes with an axis 5-15 cm long, the flowers well-spaced along the axis, the overall inflorescence much longer than its diameter
  2 Inflorescences umbellate or headlike clusters or short racemes with an axis < 2 cm long, the flowers closely clustered, the overall inflorescence little (if at all) longer than its diameter.
    3 Legumes spirally coiled or curved, often tuberculate or prickly; stems 4-angled towards the tip; leaves pinnately trifoliolate; calyx actinomorphic
    3 Legumes straight or nearly so, never tuberculate or prickly; stems terete or flattened (2-angled) towards the tip; leaves palmately 3-foliolate; calyx zygomorphic
1 Leaflets entire (and sometimes also with 1 or 2 broad lobes), or with scattered, irregular large teeth (Pachyrhizus erosus).
      4 Main stems erect or ascending, not trailing, twining, or otherwise vine-like.
        5 Flowers not papilionaceous (the wings and keel epistemonous, arising terminally or laterally from the stamen tube), barely bilaterally symmetrical; stamens 5, monadelphous; [tribe Amorpheae]
          6 Plants with separate leafy and flowering stems (the flowering stems naked or nearly so of leaves).
             7 Standard bright red, remaining folded, 30-50 mm long; leaves hastately lobed; fruit a torulose legume, 6-20 cm long, the seeds red; [tribe Phaseoleae]
             7 Standard white or pink, expanded, 4-8 mm long; leaves not hastate; fruit a flattened loment, < 5 cm long, the seeds drab; [tribe Desmodieae]
          6 Plants bearing leaves and flowers on the same stems.
               8 Leaves, stems, and/or calyces glandular-punctate.
                 9 Corollas pink or lavender/purplish; leaflets estipellate; fruit 1-seeded, indehiscent; [tribe Psoraleae]
                 9 Corollas yellow; leaflets stipellate; fruit 2-many-seeded, dehiscent; [tribe Phaseoleae, subtribe Cajaninae]
               8 Leaves, stems, and calyces lacking punctate glands.
                   10 Leaflet blades large, at least the largest terminal leaflets on a plant > 5 cm long.
                       12 Fruit a legume (not segmented into 1-seed dispersal units), hairy but the hairs not hooked; [plants cultivated as garden plants, rare as waifs]
                       12 Fruit a loment (separating into single-seeded segments), uncinulate (with hooked hairs, the fruits attaching to hairs or clothes as 'stick-tights'); [plants widespread, common]
                          13 Fruit a loment (separating into single-seeded segments), uncinulate (with hooked hairs, the fruits attaching to hairs or clothes as 'stick-tights'); [plants widespread, common]
                          13 Fruit a legume (not segmented into 1-seed dispersal units), hairy but the hairs not hooked; [plants cultivated as crops or garden plants, rare as waifs]
                            14 Keel of corolla coiled 1-3 turns; stipules conspicuous, persistent, striate; [bush green beans or lima beans]
                   10 Leaflet blades smaller, all on a plant < 5 cm long.
                                16 Fruit a loment (separating into single-seeded segments), uncinulate (with hooked hairs, the fruits attaching to hairs or clothes as 'stick-tights')
                                16 Fruit a several- to many-seeded legume, glabrous to hairy (but not uncinulate)
                                       19 Petioles fused most of length with amplexicaul stipules, the leaves thus appearing sessile or nearly so; corollas lemon to orangy yellow; flowers subsessile; fruit a loment of 2 segments, the terminal segment fertile, the lower segment either sterile or fertile
                                       19 Petioles free from stipules, leaves evidently petiolate; corollas white to pink; flowers pedicellate; fruit either 1-seeded, or a loment normally with 3+ segments
                                         20 Fruit 1-seeded; terminal leaflets 1-5 cm long, 1.2-8× as long as wide; stamens diadelphous (9 and 1)
      4 Main stems trailing, twining, creeping, or climbing or sprawling over other vegetation.
                                           21 Leaves, stems, and calyces lacking punctate glands; corollas yellow, pink, purplish, white, red, blue.
                                                      26 Fruit a loment (separating into single-seeded segments), uncinulate (with hooked hairs, the fruits attaching to hairs or clothes as 'stick-tights').
                                                                 31 Keel petal and the included style either strongly curved upwards 90-180 degrees, or even more extensively coiled (asymmetrically and spirally) in towards the flower center; stems slender to thicker, > 0.75 mm in diameter.
                                                                   32 Keel petal and the included style strongly curved upwards 90-180 degrees; corollas yellow or pink to lavender (or whitish).
                                                                     33 Corollas yellow (except pink in V. unguiculata); corolla keel symmetrical; [mainly outer Coastal Plain, introduced inland]
                                                                   32 Keel petal and the included style extensively coiled > 180 degrees (asymmetrically and spirally) in towards the flower center; corollas pink, purple, maroon, purple-black (or whitish).
                                                                       34 Peduncles short, the flowers scattered along a (sometimes branched) raceme axis, the raceme axis about as long as or longer than the peduncle; plants uncinulate pubescent (use 20× magnification, or touch the plant for the 'tacky' feel)
                                                                                    40 Keel petal and the included style either strongly curved upwards 90-180 degrees, or even more extensively coiled (asymmetrically and spirally) in towards the flower center; style or stigma pubescent.