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Key to Fabaceae, Key I: herbaceous legumes with all leaves unifoliolate or leaflets absent [subfamily Faboideae]

Fabaceae

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1
Tendrils present on plant; leaves modified into tendrils (leaflike structures present clearly interpretable as stipules); [tribe Fabeae].
  2
Legume 4-7 mm wide; corolla 10-13 mm long
 ⇒ Lathyrus aphaca
  2
Legume 12-20 mm wide; corolla 18-25 mm long
 ⇒ Pisum
1
Tendrils absent; leaves or stipules present on plant and interpretable as leaves with 1 leaflet.
  3
Leaflet blades roundish, 0.6-1.5× as long as wide.
    4
Leaves with a well-developed petiole, > 0.5 cm long.
      5
Leaflet margins dentate; corollas white to pink; [tribe Psoraleeae]
 ⇒ Cullen corylifolium
      5
Leaflet margins entire; corollas yellow; [tribe Phaseoleae]
 ⇒ Rhynchosia
    4
Leaves sessile, subsessile, or perfoliate.
      6
Corolla bright or creamy yellow; stamens separate; leaves all 1-foliolate; leaflet blades perfoliate or sessile; [tribe Thermopsideae]
 ⇒ Baptisia
      6
Corolla violet to blue (drying pale); stamens diadelphous; leaves 1-foliolate and with some leaves 3-foliolate or 2-foliolate; leaflet blades cuneate, subsessile; [tribe Psoraleeae]
 ⇒ Pediomelum canescens
  3
Leaflet blades elongate, 1.5-15× as long as wide.
    7
Leaves basally disposed.
      8
Leaflet blades elliptic, widest near the midpoint of the blade; flowers pink, rose, or purplish; legume straight; [native of the Coastal Plain, se. NC south to s. FL, west to e. LA]; [tribe Genisteae]
 ⇒ Lupinus
      8
Leaflet blades oblanceolate, widest well past the midpoint of the blade; flowers yellow; legume coiled; [rare waif]; [tribe Loteae]
 ⇒ Scorpiurus muricatus
    7
Leaves all or primarily cauline.
      9
Leaves long-petioled, the petiole > 2 cm long.
        10
Petiole winged its entire length; leaflet blade 2-4× as long as wide, sagittate at the base; foliage not glandular; [tribe Phaseoleae]
 ⇒ Centrosema sagittatum
        10
Petiole not winged; leaflet blade 8-15× as long as wide, cuneate at the base; foliage glandular-punctate; [tribe Psoraleeae]
 ⇒ Orbexilum virgatum
      9
Leaves sessile, subsessile, or short-petiolate, the petiole < 1.5 cm long.
        11
Stamens monadelphous; corolla yellow, 8-30 mm long; [tribe Crotalarieae]
 ⇒ Crotalaria
        11
Stamens diadelphous; corolla purple, lavender, or cream, 5-15 mm long.
          12
Corolla 11-15 mm long, purple; [se. and s. TX]; [tribe Diocleae]
 ⇒ Nanogalactia heterophylla
          12
Corolla 5-7 mm long, lavender or cream; [widespread in our area]
             13
Flowers solitary in leaf axils; [tribe Loteae]
 ⇒ Acmispon
             13
Flowers in racemose inflorescences; [tribe Desmodieae]
 ⇒ Alysicarpus