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Key to Fabaceae

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1 Trees, shrubs, or woody vines; [subfamilies Caesalpinioideae, Mimosoideae, and Faboideae]
..2 Leaves 1-3-foliolate, or leaves reduced to flattened phyllodia or phyllodial spines.
..2 Leaves 4-many-foliolate.
....3 Leaves bipinnately compound
....3 Leaves pinnately compound.
......4 Leaves evenly 1-pinnate, with 1 or more lateral pairs of leaflets and 0 terminal leaflet
......4 Leaves oddly 1-pinnate, with a terminal leaflet
1 Herbs (including herbaceous vines).
........5 Leaves 4-many-foliolate.
..........6 Leaves palmately compound, with 4 or more leaflets; [subfamily Faboideae]
..........6 Leaves pinnately or bipinnately compound.
............ 7 Leaves bipinnately compound
............ 7 Leaves pinnately compound
............ ..8 Leaves evenly 1-pinnate, with 1 or more lateral pairs of leaflets and 0 terminal leaflet
............ ..8 Leaves oddly 1-pinnate, with a terminal leaflet
........5 Leaves 0-3-foliolate ; [subfamily Faboideae].
............ ....9 Leaves 2-foliolate
............ ....9 Leaves 0, 1, or 3-foliolate.
............ ......10 Leaves unifoliolate, or with leaf or leaflet blades absent, replaced by a tendril (and with foliaceous stipules)
............ ......10 Leaves trifoliolate (plants with some upper stem or lower stem leaves unifoliolate but with other trifoliolate leaves should be keyed here).
............ ........11 Leaves palmately 3-foliolate (the petiolules of the 3 leaflets usually of similar length (if the apparent petiolule of the terminal leaflet is slightly longer, it does not have a joint between a rachis and the petiolule of the terminal leaflet)
............ ........11 Leaves pinnately 3-foliolate

Key to Fabaceae, Key A: woody legumes with all leaves 1-, 2-, or 3-foliolate, or reduced to flattened phyllodia or phyllodial spines

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1 Stamens numerous; inflorescences of many flowers arranged in a closely packed sphere or cylinder; leaves replaced by phyllodes, these leathery in texture and often crescent-shaped; [Mimosoid clade]
1 Stamens 10 (or fewer); inflorescences various, the flowers larger and more diffuse; leaves 1-, 2-, or 3-foliolate, or reduced to phyllodial apines; [subfamily Faboideae or Cercidioideae]
..2 Leaves 1- or 2-foliolate and > 2 cm wide; trees, shrubs, or lianas.
....3 Seeds 1-2 (-4) per fruit; corolla pale yellow, pale pink, or white; longest petals 7-10 mm long; [subfamily Faboideae]
....3 Seeds > 5 per fruit; corolla purplish-pink, bright pink, or white; longest petals 10-100 mm long [subfamily Cercidioideae]
......4 Leaves with a rounded to apiculate apex; flowers strongly bilaterally symmetrical, “pseudopapilionoid”; petals 0.8-1.5 cm long; legumes 4-10 cm long; [natives and aliens, and widely cultivated]
......4 Leaves either unifoliolate with a deeply notched apex or 2-foliolate; flowers slightly bilaterally symmetrical; petals 1.5-8 (-10) cm long; legumes 7-30 cm long; [aliens, of FL peninsula].
........5 Shrub or tree; petals 3-8 (-10) cm long
........5 Liana (climbing by twining and by tendrils); petals 1.5-2.0 cm long
..2 Leaves 3-foliolate, or reduced to phyllodial spines, or 1-foliolate (but then < 2 cm wide); shrubs or woody vines (rarely trees in Erythrina); [subfamily Faboideae].
..........6 Woody vine (Pueraria, a robust herbaceous vine, is also keyed here as a failsafe).
............ 7 Leaves glandular beneath; terminal leaflets 1.3-4 cm long
............ 7 Leaves eglandular beneath; terminal leaflets 5-20 cm long.
............ ..8 Terminal leaflet 1.5-2.5× as long as wide; corolla yellow; legume 4-6 cm wide; seeds 2-3 cm wide
............ ..8 Terminal leaflet 0.8-1.3× as long as wide; legume 0.8-1.3 cm wide; seeds < 1 cm wide; corolla purplish or red.
............ ....9 Calyx 4.5-6 mm long; leaflets unlobed; [tribe Phaseoleae]
............ ....9 Calyx 10-12 mm long; leaflets generally lobed; [tribe Phaseoleae]
..........6 Shrub or tree.
............ ......10 Shrub with angled or flanged green twigs; leaves palmately trifoliolate, unifoliolate, or reduced to spine-tipped phyllodes; [introduced]; [tribe Genisteae].
............ ........11 Flowers red-purple; calyx 2-3 mm long; [tribe Galegeae]
............ ........11 Flowers bright yellow; calyx 3-15 mm long; [tribe Genisteae]
............ ..........12 Leaves all reduced to phyllodial spines; flowers axillary; calyx 10-15 mm long
............ ..........12 Leaves with normal lamina, either 1-foliolate or 3-foliolate; flowers in terminal racemes; calyx 3-6 mm long.
............ ............ 13 Leaves 3-foliolate lower on the stem, often 1-foliolate above; corolla 15-22 mm long
............ ............ 13 Leaves 1-foliolate throughout; corolla either 10-14 mm or 20-25 mm long
............ ............ ..14 Corolla 10-14 mm long; fruits 1.5-3 cm long
............ ............ ..14 Corolla 20-25 mm long; fruits 5-10 cm long
............ ......10 Shrub or tree with twigs various, but not conspicuously green or flanged; leaves pinnately trifoliolate or unifoliolate.
............ ............ ....15 Leaflet margins toothed; [rare waif]; [tribe Trifolieae]
............ ............ ....15 Leaflet margins entire; [collectively common and widespread].
............ ............ ......16 Leaves unifoliolate; [tribe Genisteae]
............ ............ ......16 Leaves pinnately trifoliolate.
............ ............ ........17 Corolla 15-50 mm long, yellow or scarlet; legume with several seeds; leaflets lobed or not; [tribe Phaseoleae]
............ ............ ..........18 Corolla 15-21 mm long, yellow; leaflets unlobed; leaflets densely yellow glandular-punctate
............ ............ ..........18 Corolla 30-50 mm long, scarlet; leaflets lobed or not; leaflets eglandular
............ ............ ........17 Corolla 8-15 mm long, purplish, pink, or white; legume 1-seeded; leaflets not lobed.
............ ............ ............ 19 Foliage glandular-punctate; [tribe Psoraleae]
............ ............ ............ 19 Foliage eglandular; [tribe Desmodieae]

Key to Fabaceae, Key B: woody legumes (trees, shrubs, or woody vines) with bipinnately compound leaves

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1 Leaves variously modified from strict 2-even-pinnateness, either with 1) a mixture (on a tree) of 1-even-pinnate and 2-even-pinnate leaves, and/or 2) the pinnae or leaflets often subopposite or fully alternate, and/or 3) with an odd number of pinnae per leaf (the tip of the rachis with a pair of lateral pinnae and a terminal pinna, but the leaflets of the pinnae still in opposite pairs), and/or 4) the basal pair of pinnae evolutionarily replaced by a single pair of leaflets larger than the other leaflets.
..2 Flowers small, inconspicuous, in catkin like-racemes or racemes of racemes; perianth greenish-white or greenish-yellow, with a cylindrical hypanthium to 10 mm long and shorter perianth lobes; flowers mostly unisexual; large trees; fruits woody and indehiscent at maturity, 1-5 cm wide[ collectively widespread in our region, but absent from s. FL and s. TX].
....3 Leaves characteristically a mixture (on a tree) of 1-even-pinnate (mainly on spurs) and 2-even-pinnate (mainly on new growth), the pinnae and the leaflets strictly opposite or subopposite; leaflets 1.5-4 cm long, acute to rounded at the apex; trunks with simple, trident, or multiply branched thorns to 20 cm long (or unarmed)
....3 Leaves all 2-even-pinnate, the basalmost "pinna pair" usually replaced by a pair of leaflets larger than the others, the pinnae and the leaflets often 'straying' to subopposite or fully alternate arrangement (some pinnae appearing odd-pinnate); leaflets 3-6 cm long, acuminate at the apex; trunks unarmed
..2 Flowers either with conspicuous petals or aggregated into spikes or spherical heads with showy stamens; petals either (Caesalpinoids) yellow, orange, red, or (Mimosoids) the tubular perianth whorls less conspicuous than the stamens, these yellow to orange; flowers bisexual; small shrubs, shrubs, small or medium trees, or large trees (if large trees, then of tropical parts of our region); fruits papery or chartaceous (rarely woody), often < 2 cm wide; [collectively widespread, including of s. FL and s. TX].
......4 Leaves with pinnae and leaflets mostly subopposite or fully alternate; [exotic, s. FL]; [Mimosoid]
......4 Leaves with an odd number of pinnae per leaf (the tip of the rachis with a pair of lateral pinnae and a terminal pinna), but the leaflets in opposite pairs; [native or exotic, TX and OK]; [Caesalpinoid].
........5 Shrub or small tree, 5-50 dm tall; sepals ovate; leaflets not gladular, or with glands only along the leaflet margin
........5 Sprawling shrub, less than 6 dm tall; sepals linear; leaflets glandular punctate across the lower surface (these orange in life, drying black)
1 Leaves strictly 2-even-pinnate (with pinna pairs borne opposite one another and no pinna terminal on the rachis, and with leaflets also born in opposite pairs).
..........6 Pinna pairs 1-6 (-7) per leaf; leaflets 4-ca. 250 per leaf.
............ 7 Leaflets 1.5-14 mm long.
............ ..8 Glands absent on petioles and rachises.
............ ....9 Dwarf shrub, 1-6 dm tall; branches unarmed.
............ ....9 Shrub, small tree, or scrambling liana; branches armed with straight nodal spines or internodal catclaw prickles.
............ ......10 Branches armed with paired, straight, nodal spines, these simple or 3-branched; branches and larger stems green, photsynthetic; flowers caesalpinoid, 2-2.5 cm in diameter.
............ ......10 Branches armed with catclaw prickles scattered along internodes; branches and stems brown; flowers caesalpinoid or mimosoid.
............ ........11 Scrambling liana; flowers caesalpinoid, 1.5-2 cm across
............ ........11 Shrub; flowers mimosoid, aggregated into spherical inflorescences 9-15 mm in diameter
............ ..8 Glands (stalked, columnar, or domed) 1 or more on petioles or rachises, on the petiole or at rachis nodes.
............ ..........12 Branches unarmed.
............ ............ 13 Stamens connate basally into a tube; spherical inflorescences whitish or cream, 15-23 mm in diameter
............ ............ 13 Stamens free; spherical inflorescences yellow, 6-8 mm in diameter
............ ..........12 Branches armed with straight nodal spines or internodal catclaw prickles.
............ ............ ..14 Branches armed with catclaw prickles scattered along internodes.
............ ............ ..14 Branches armed with paired, straight, nodal spines.
............ ............ ....15 Leaflet pairs 2-6 per pinna; inflorescences cylindrical.
............ ............ ......16 Petiolar/rachis glands at nodes of the rachis, short-columnar; stamens connate basally into a tube
............ ............ ......16 Petiolar/rachis gland on the petiole; stamens free
............ ............ ....15 Leaflet pairs 6-25 per pinna; inflorescences spherical (or cylindrical in Prosopis laevigata).
............ ............ ........17 Inflorescences cylindrical; leaflet pairs 15-27 per pinna
............ ............ ........17 Inflorescences spherical; leaflet pairs 6-20 per pinna.
............ ............ ..........18 Dwarf shrub; pinna pair 1 per leaf; leaflet pairs 6-11 per pinna; fruit spirally twisted into a cylinder
............ ............ ..........18 Shrub or small tree; pinna pairs 2-5 (-6) per leaf; leaflet pairs 9-20 per pinna; fruit flat, straight.
............ ............ ............ 19 Spherical inflorescences 15-23 mm in diameter; stamens connate basally into a tube; fruits flat, about 1 cm wide, 2-4 mm thick
............ ............ ............ 19 Spherical inflorescences 6-13 mm in diameter; stamens free; fruits turgid, cylindrical, about 1 cm in diameter (wide and thick)
............ 7 Leaflets 10-60 mm long (at least the larger leaflets on a plant > 14 mm long).
............ ............ ............ ..20 Glands absent on petioles and rachises.
............ ............ ............ ....21 Pinna pairs 1 per leaf; branches unarmed; flowers red-pink, mimosoid, aggregated into spherical inflorescences 5-7 cm in diameter
............ ............ ............ ....21 Pinna pairs 2-5 per leaf; branches armed with catclaw prickles scattered along internodes; flowers yellow to orange, caesalpinoid, each flower 0.7-2 cm across.
............ ............ ............ ......22 Liana climbing and sparawling over other vegetation; flowers 0.7-1 cm across
............ ............ ............ ......22 Shrub or small tree; flowers 1.8-2 cm across
............ ............ ............ ..20 Glands (stalked, columnar, or domed) 1 or more on petioles or rachises, on the petiole or at rachis nodes.
............ ............ ............ ........23 Leaflet pair 1 per pinna
............ ............ ............ ........23 Leaflet pairs 3-14 per pinna
............ ............ ............ ..........24 Branches usually armed with paired, straight, nodal spines; inflorescences cylindrical; stamens 10
............ ............ ............ ..........24 Branches unarmed; inflorescences spherical; stamens many.
............ ............ ............ ............ 25 Stamens free
............ ............ ............ ............ 25 Stamens connate basally into a tube.
............ ............ ............ ............ ..26 Petiolar gland near base of petiole; spherical inflorescences either 0.9-1.7 cm in diameter, or 5-6 cm in diameter
............ ............ ............ ............ ..26 Petiolar gland closer to first pinna pair than to petiole base; spherical inflorescences 2-2.6 cm in diameter
..........6 Pinna pairs 4-25 per leaf (at least the larger leaves on a plant with > 6 pinna pairs); leaflets 150-3000 per leaf.
............ ............ ............ ............ ....27 Leaflets 10-40 mm long, at least the larger on a leaf > 15 mm long.
............ ............ ............ ............ ......28 Leaf rachis eglandular; flowers caesalpinoid, each yellow-orange and 3-4 cm across
............ ............ ............ ............ ......28 Leaf rachis with cupular glands at nodes; flowers mimosoid, pink, aggregated into a spherical head 5-6 cm in diameter
............ ............ ............ ............ ....27 Leaflets 1-15 mm long.
............ ............ ............ ............ ........29 Glands absent on petioles and rachises.
............ ............ ............ ............ ..........30 Branches armed with catclaw prickles scattered along internodes; shrub; flowers mimosoid, white, cream, or pink, aggregated into spherical heads 0.9-2 cm in diameter.
............ ............ ............ ............ ..........30 Branches unarmed; tree; flowers caesalpinoid, each yellow and 2-3.5 cm across
............ ............ ............ ............ ........29 Glands (stalked, columnar, or domed) or nonglandular spheroid projections 1 or more on petioles or rachises, on the petiole or at rachis nodes.
............ ............ ............ ............ ............ 31 Branches unarmed.
............ ............ ............ ............ ............ ..32 Fruits 30-60 cm long, woody, persistent and indehiscent on the tree; flowers caesalpinoid, scarlet and yellow, 8-10 cm across; rachis with spheroidal projections at the nodes; petiole lacking glands
............ ............ ............ ............ ............ ..32 Fruits < 20 cm long, papery, coriaceous, or woody; flowers mimosoid, white, cream, pink, or pale yellow, aggregated into spherical heads 1-6 cm in diameter; rachis lacking spheroidal projections; petiole bearing domed or saucer-shaped glands along the petiole or at the 1st pair of pinnae.
............ ............ ............ ............ ............ ....33 Spherical heads pink, 2.5-6 cm in diameter
............ ............ ............ ............ ............ ....33 Spherical heads white, cream, or pale yellow, 0.5-2.2 cm in diameter.
............ ............ ............ ............ ............ ......34 Fruits strongly coiled; stamens many; tree
............ ............ ............ ............ ............ ......34 Fruits strait or slightly curved; stamens 10; tree or shrub.
............ ............ ............ ............ ............ ........35 Stipules persistent and evident, 3-10 mm long; fruits 5.5-8.5 cm long, 2-5 mm wide
............ ............ ............ ............ ............ ........35 Stipules caducous; fruits 8-20 cm long, 10-20 mm wide
............ ............ ............ ............ ............ 31 Branches variously armed, with nodal spines, thorn spurs, or catclaw prickles scattered along internodes.
............ ............ ............ ............ ............ ..........36 Branches armed with catclaw prickles scattered along the internodes
............ ............ ............ ............ ............ ..........36 Branches armed either with woody thorn spurs or paired nodal spines.
............ ............ ............ ............ ............ ............ 37 Branches armed with stout thorn spurs (these simple or branched); inflorescences cylindrical, bicolored, the base of pink or whitish staminodes, the tip of yellow stamens; fruits flattened, but also curved and contorted
............ ............ ............ ............ ............ ............ 37 Branches armed with paired nodal spines, these either narrow and needle-like or massive, hollow, and with an entrance hole; fruits turgid, straight or slightly curved

Key to Fabaceae, Key C: woody legumes with evenly 1-pinnately compound leaves with 2 or more leaflets
[subfamilies Faboideae and Caesalpinioideae]

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1 Flowers with 5 petals, 2 fused to form the keel (papilionaceous); corolla rose, yellow, orange, red, pink, or white; [subfamily Faboideae].
..2 Lianas climbing by twining; stamens 9, monadelphous
..2 Shrubs; stamens 10, diadelphous (9 and 1).
....3 Leaflet pairs 10-25; [widespread]
....3 Leaflet pairs 4-6.
......4 Leaflets 10-25 mm long; corolla 15-20 mm long, yellow; [non-native cultivated and sparingly established]
......4 Leaflets 3-11 mm long; corolla 8-11 mm long, pink or white; [native, s. TX]
1 Flowers with 5 or 3 petals, all distinct (caesalpinaceous); corolla yellow, orange, red, or pink; [subfamily Detarioideae or Caesalpinioid clade].
........5 Large tree; sepals 4; petals 3; functional stamens 3; [subfamily Detarioideae]
........5 Shrub or small tree (< 5 m tall); sepals 5, petals 5, functional stamens 6-10; [Caesalpinoid clade].
..........6 Trees; filaments of the 3 lower stamens curved; petiolar gland absent; [introduced in s. FL]
..........6 Shrubs or trees; filaments of all stamens straight; petiolar and/or rachis gland(s) present or absent; [collectively more widespread].
............ 7 Leaflets 0.6-1.0 cm long, coriaceous, the venation raised-reticulate below; functional stamens 10; [s. TX]
............ 7 Leaflets 1.5-10.5 cm long, herbaceous; functional stamens 6-7 (10 in S. surattensis); [collectively more widespread, but especially FL and s. TX]

Key to Fabaceae, Key D: woody legumes with oddly 1-pinnately compound leaves with 5 or more leaflets
[subfamilies

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1 Liana, climbing by twining; [tribe Millettieae]
..2 Inflorescence a stiff panicle; leaflets (5-) 7-9; ovary and fruit glabrous; leaves evergreen
..2 Inflorescence a pendent raceme; leaflets 7-19; ovary and fruit either glabrous or densely velvety-villous; leaves cold-deciduous
1 Shrubs and trees, lacking climbing adaptations.
....3 Leaflets glandular-punctate (not requiring magnification).
......4 Leaflets 4-10 cm long; leaves with 7-13 leaflets; large tree; flowers ca. 15 mm long, pink-purple; [tribe Milletieae]
......4 Leaflets 0.4-4 (-7) cm long; leaves with (7-) 9-31 leaflets; shrub or small tree; flowers 4-11 mm long, white, cream, violet, purple, or blue; [tribe Amorpheae].
........5 Corolla reduced to a single petal (the standard); flowers whitish, sky blue, dark blue, purple, or violet; [collectively widespread]
........5 Corolla of 5 petals; flowers white to cream, sometimes 'fading' to dark purple; [s. FL, TX].
..........6 Flowers papilionoid, either cream, fading purplish, or bicolored white and purple; [s. FL, TX, OK]
..........6 Flowers only slightly bilaterally symmetrical, white; [TX]
....3 Leaflets lacking punctate glands.
............ 7 Leaflets 3-9 per leaf; leaflets 2-15 (-20) cm long; small or large tree (to shrub in Dermatophyllum secundiflorum).
............ ..8 Lateral leaflets all or mostly alternate along the rachis.
............ ....9 Leaflets (5-) 7-9 per leaf; flowers 18-25 mm long, white; [native, also planted; SC, GA, AL, MS, and LA northwards]
............ ....9 Leaflets 3-5 (-7) per leaf; flowers ca. 10 mm long, yellow-white or pinkish; [non-native; FL peninsula]
............ ..8 Lateral leaflets strictly in opposite pairs.
............ ......10 Stamens free; [tribe Sophoreae].
............ ........11 Corollas 14-16 mm long, blue-purple; fruit turgid and cylindrical, but torulose-constricted between the scarlet seeds; [native; TX]
............ ........11 Corollas 7-11 mm long, cream to white; fruit flattened, not constricted between the tan to light brown seeds; [non-native]
............ ......10 Stamens monadephous or diadelphous; [FL peninsula]; [tribe Milletieae]
............ ..........12 Fruit woody, unwinged, with 1 very large (ca. 2 cm long) seed; stamens diadelphous
............ ..........12 Fruit 2-9 cm long, membranaceous, with 4 broad, tan, ruffled wings and 1-6 black seeds; stamens monadelphous
............ 7 Leaflets (5-) 7-31 per leaf, at least the larger and better developed leaves on a plant with 11 or more leaflets; leaflets 0.4-12 cm long; shrub, small tree, or large tree.
............ ............ 13 Corollas 5-6 mm long, pink or purplish; fruits 15-35 mm long, 1-3 mm wide
............ ............ 13 Corollas 9-30 mm long, yellow, white, pink, or purplish; fruits 25-150 (-200) mm long, 5-35 mm wide.
............ ............ ..14 Corollas ca. 10 mm long, pink or purplish; fruit a single-seeded, globose or broadly ellipsoid drupe, 2.5-4 cm long, 2-3 cm in diameter; leaflets 4-12 cm long; [s. FL]
............ ............ ..14 Corollas 15-30 mm long, white, pink, purplish, or bright yellow or coppery; fruit a legume, seeds several; leaflets 2-6 cm long; [collectively widespread]
............ ............ ....15 Corollas bright yellow or coppery; fruits about as thick as wide, either bladdery-inflated or moniliform (like beads on a string).
............ ............ ......16 Fruits bladdery-inflated, 50-70 mm long, 20-30 mm in diameter; stamens diadelphous; [cultivated ornamental, rarely establishing]
............ ............ ......16 Fruits moniliform (like beads on a string), 100-200 mm long, 7-8 mm in diameter at the seeds, 1-2 mm in diameter between the seeds; stamens free; [native of coastal peninsular FL and TX].
............ ............ ....15 Corollas white, pink, or pink-purple; fruits flattened (wider than thick).
............ ............ ........17 Leaflets short-acuminate at the apex; calyx truncate-sinuate at its apex; branches not armed; [tropical s. FL]
............ ............ ........17 Leaflets rounded, obtuse, or retuse (and also usyually with a noticeable mucro) at the apex; calyx with lobes at its apex; branches sometimes armed with stipular (nodal) spines or internodal hispid hairs; [temperate, widespread in our region]

Key to Fabaceae, Key E: herbaceous legumes with palmate leaves with 4 or more leaflets [subfamily Faboideae]

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1 Leaflets 4; corolla yellow; [tribe Dalbergieae]
1 Leaflets 5 or more (at least on the largest and best developed leaves); corolla blue, pink, or violet (except yellow in Lupinus luteus).
..2 Leaflets and fruits not glandular-punctate; stamens monadelphous; [tribe Genisteae]
..2 Leaflets and fruits glandular-punctate; stamens diadelphous; [tribe Psoraleeae].
....3 Leaflets linear to very narrowly oblanceolate, 0.5-2.0 (-3.5) mm wide, > 10× as long as wide; [Coastal Plain]
....3 Leaflets broader, > 5 mm wide, 2-4.5× as long as wide; [collectively more widespread]

Key to Fabaceae, Key F: herbaceous legumes with bipinnate leaves [subfamily Mimosoideae]

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1 Leaves with an odd number of pinnae (lateral pinnae paired, but an additional pinna present in a terminal position on the rachis); [Caesalpinoideae].
..2 Leaflets 0.9-1.6× as long as wide; terminal pinna with about 2× as many leaflet pairs (8-20) as the lateral pinnae (3-7)
..2 Leaflets 1.8-4× as long as wide; terminal pinna with about the same number of leaflet pairs as the lateral pinnae.
....3 Lower surfaces of leaflets eglandular
....3 Lower surfaces of leaflets densely glandular punctate, the glands orange when fresh and drying black
1 Leaves with an even number of pinnae (lateral pinnae paired).
......4 Coarse climbing or sprawling suffruticose herbs, the stems to 6 m long, and usually armed with retrorsely curved prickles; [Caesalpinoidaeae]
......4 Perennial herbs, less coarse; [Mimosoideae]
........5 Stamens > 10; [tribe Acacieae]
........5 Stamens 10 or fewer; [tribe Mimoseae].
..........6 Petiole with 1-several glands; stems ascending to erect; flowers greenish-white
..........6 Petiole without glands; stems prostrate to weakly arching; flowers pink-purple, yellow, or greenish-yellow.
............ 7 Flowers pink-purple; legume ribbed, the ribs with prickles
............ 7 Flowers yellow to greenish-yellow; legume not ribbed or prickly

Key to Fabaceae, Key G: herbaceous legumes with once-pinnately, even-pinnately compound (or 'palmately' 2-foliolate) leaves with 2 or more leaflets
[subfamilies Faboideae and Caesalpinioideae]

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1 Flowers nearly regular; stamens 5-10, separate; [subfamily Caesalpinioideae, tribe Cassieae].
..2 Leaflets 5-25 pairs, each leaflet 0.5-1.5 cm long; stipules persistent, striate
..2 Leaflets (2-) 3-12 pairs, each leaflet 1.5-12 cm long; stipules caduceus, small, not striate
1 Flowers papilionoid; stamens diadelphous or monadelphous; [subfamily Faboideae].
....3 Tendrils lacking on all leaves; stamens monadelphous or diadelphous.
......4 Leaflets 2 per leaf; [tribe Aeschynomeneae]
......4 Leaflets 4-60 per leaf.
........5 Floating aquatic with stems swollen, inflated
........5 Terrestrial plants with stem not swollen
..........6 Leaflets 20-60 per leaf; strong herbs (or woody) 1-4 m tall, simultaneously erect, > 1 m tall, and with stems usually > 5 mm in diameter
............ 7 Fruit a loment, with single-seeded segments separated by sutures; stamens monadelphous or diadelphous in 2 phalanges of 5; [tribe Aeschynomeneae]
............ 7 Fruit a legume; stamens diadelphous; [tribe Sesbanieae]
..........6 Leaflets 4-18 per leaf; weak or sprawling herbs to 1.5 m long, with weak stems usually < 5 mm in diameter (or if thicker, then < 1 m long; stamens monadelphous or diadelphous.
............ ..8 Leaflets 4 per leaf; stamens monadelphous; [tribe Dalbergieae]
............ ..8 Leaflets 4-16 per leaf; stamens monadelphous, diadelphous (9 and 1, or 5 and 5)
............ ....9 Stamens monadelphous or diadelphous in 2 phalanges of 5 and 5; [tribe Aeschynomeneae]
............ ....9 Stamens diadelphous (9 and 1); [tribe Fabeae]
....3 Tendrils present in the terminal position on some or all leaves; stamens diadelphous; [tribe Fabeae].
............ ......10 Stipules foliaceous, typically larger than the leaflets
............ ......10 Stipules smaller, typically much smaller than the leaflets.
............ ........11 Calyx lobes 2-4× as long as the calyx tube; [rare waif]
............ ........11 Calyx lobes 1-2× as long as the calyx tube; [collectively widespread and common].
............ ..........12 Style stout, flattened or folded, with a dense longitudinal band of hairs longitudinally arrayed along the inner side; stems ridged, angled, or longitudinally winged; leaflets 2-6 (-8) cm long; calyx 5-12 mm long
............ ..........12 Style slender and hair-like, terete (round in ×-section), glabrous except for a ring of short hairs just below the stigma; stems ridged or angled, but not longitudinally winged; leaflets 0.5-4.5 cm long (except larger in a few waifs); calyx 2-8 mm long (except larger in a few waifs)

Key to Fabaceae, Key H: herbaceous legumes with once-pinnately, odd-pinnately compound leaves with 5 or more leaflets
[subfamilies Faboideae and Caesalpinioideae]

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1 Lateral veins of each leaflet neatly straight and parallel to one another; [tribe Millettieae]
1 Lateral veins of each leaflet complicatedly and less regularly arrayed.
..2 Leaves (at least the largest and those with the most leaflets) with ≥ 13 leaflets.
....3 Ovaries (and later fruits) with dense, hooked prickles (looking like a miniature cocklebur, Xanthium); leaves and stems glandular-punctate with brown or black glands; stamens diadelphous (9 and 1); [rare waif in our area]; [tribe Galegeae]
....3 Ovaries (and later fruits) glabrous, glandular, or hairy; leaves and stems glabrous, variously hairy, but not glandular-punctate (except Dalea); stamens 5-10, monadelphous, diadelphous, or separate; [collectively widespread].
......4 Leaflets conspicuously dentate; [tribe Cicereae]
......4 Leaflets entire.
........5 Hairs dolabriform (with 2 branches parallel to the surface and pointing at 180° from each other).
..........6 Petals reddish orange and/or with some pink or salmon; [tribe Indigofereae]
..........6 Petals pink-purple to violet; [tribe Galegeae]
........5 Hairs basifixed.
............ 7 Fruit a loment (jointed between each seed and splitting into single-seeded segments).
............ ..8 Loments cylindrical, jointed but not noticeably constricted between the seeds; Inflorescence an umbel of (7-) 10-15 flowers; [tribe Loteae]
............ ..8 Loments flattened, prominently constricted between the seeds; inflorescence a raceme or umbel of 2-8 flowers.
............ ....9 Corolla primarily white to pink; loments 1-2.5 cm long, not borne on a stipe; [tribe Coronilleae]
............ ....9 Corolla primarily yellow (sometimes also marked with pink or orange); loments 2-5 cm long, borne on a 1-20 mm long stipe (above the calyx); [tribe Dalbergieae]
............ 7 Fruit a legume (lacking joints between each seed, though sometimes the pod constricted).
............ ......10 Inflorescences pedunculate, axillary racemes; leaflets eglandular; fruits dehiscent; [tribe Galegeae]
............ ......10 Inflorescences terminal racemes, spikes, or heads; leaflets glandular-punctate or not; fruits indehiscent.
............ ........11 Fruit 1-seeded; leaflets glandular-punctate; [tribe Amorpheae]
............ ........11 Fruit with several seeds; leaflets eglandular; [tribe Sophoreae]
..2 Leaves (the largest and those with the most leaflets) with < 11 leaflets.
............ ..........12 Fruit a loment (constricted between each seed and splitting into single-seeded segments); petals primarily yellow (sometimes also marked with pink or orange); [of the se. Coastal Plain, from e. GA southwards and westwards]; [tribe Dalbergieae].
............ ............ 13 Stems ascending or erect; loment subterete
............ ............ 13 Stems prostrate, trailing; loment flattened
............ ..........12 Fruit a legume (lacking constrictions between the seeds); petals variously colored; [collectively widespread].
............ ............ ..14 Ovaries (and later fruits) with dense, hooked prickles; leaves and stems glandular-punctate with brown or black glands; stamens diadelphous (9 and 1); [rare waif in our area]; [tribe Galegeae]
............ ............ ..14 Ovaries (and later fruits) glabrous, glandular, or hairy; leaves and stems glabrous, variously hairy, but not glandular-punctate (except Dalea); stamens 5-10, monadelphous, diadelphous, or separate; [collectively widespread].
............ ............ ....15 Plants with basal rosettes, the basal and cauline leaves a mixture of simple and pinnately compound; [rare waif in our area]; [tribe Loteae]
............ ............ ....15 Plants with primarily cauline leaves, all pinnately compound; [collectively widespread].
............ ............ ......16 Plants erect or ascending herbs.
............ ............ ........17 Leaves with 5 leaflets, the 2 basal leaflets positioned like stipules at the base of the leaf (the leaf thus sessile); [tribe Loteae]
............ ............ ........17 Leaves with 5-9 (or fewer or more and then keyed elsewhere), the lower leaflets positioned above a definite petiole.
............ ............ ..........18 Hairs dolabriform (with 2 branches parallel to the surface and pointing at 180° from each other; petals reddish orange and/or with some pink or salmon; flowers papilionaceous; stamens 10, diadelphous (9+1); leaflets often > 5 mm wide; legume 3+-seeded; flowers 5-12 mm long, in racemes; [tribe Indigofereae]
............ ............ ..........18 Hairs basifixed; petals of various colors; flowers not papilionaceous, barely bilaterally symmetrical; stamens 5, monadelphous; leaflets 0.5-5 mm wide; legume 1-seeded; flowers very small, < 5.5 mm long, aggregated into tight spike; [tribe Amorpheae]
............ ............ ......16 Plants prostrate or twining herbaceous vines.
............ ............ ............ 19 Hairs dolabriform (with 2 branches parallel to the surface and pointing at 180° from each other; petals reddish orange and/or with some pink or salmon; [tribe Indigofereae]
............ ............ ............ 19 Hairs basifixed; petals of various colors; [tribe Phaseoleae].
............ ............ ............ ..20 Flower usually solitary, resupinate (twisted at 180° so that the standard is below); standard 3.5-5 cm long
............ ............ ............ ..20 Flowers few to many in racemes, normally oriented (with the standard above); standard < 2.5 cm long.
............ ............ ............ ....21 Corolla purplish, maroon, brownish, or yellowish green; leaflets 4-9 cm long, on petioles 3-5 mm long; keel coiled
............ ............ ............ ....21 Corolla either white with red striations or lavender; leaflets 2-5 cm long, on petioles 1-2 mm long; keel carinate, not coiled

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

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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
..2 Legume 12-20 mm wide; corolla 18-25 mm long
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]
........5 Leaflet margins entire; corollas yellow; [tribe Phaseoleae]
......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]
..........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]
....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]
............ ..8 Leaflet blades oblanceolate, widest well past the midpoint of the blade; flowers yellow; legume coiled; [rare waif]; [tribe Loteae]
............ 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]
............ ......10 Petiole not winged; leaflet blade 8-15× as long as wide, cuneate at the base; foliage glandular-punctate; [tribe Psoraleeae]
............ ....9 Leaves sessile, subsessile, or short-petiolate, the petiole < 1.5 cm long.
............ ........11 Stamens monadelphous; corolla yellow, 8-30 mm long; [tribe Crotalarieae]
............ ........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]
............ ..........12 Corolla 5-7 mm long, lavender or cream; [widespread in our area]
............ ............ 13 Flowers solitary in leaf axils; [tribe Loteae]
............ ............ 13 Flowers in racemose inflorescences; [tribe Desmodieae]

Key to Fabaceae, Key J: herbaceous legumes with palmately trifoliolate leaves [subfamily Faboideae]

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1 Stamens separate, unfused; stipules (at least the lower on the stem) often persistent, foliaceous, not striate; corollas yellow, white, or purple-blue.
..2 Legumes turgid, inflated; corolla white, cream, yellow, blue, or purple; [widespread in our area, especially Coastal Plain]
..2 Legumes laterally compressed; corolla yellow; [primarily montane, elsewhere as an escape from cultivation]
1 Stamens monadelphous or diadelphous; stipules either caducous or well-developed and persistent, and then separate or adnate to the petiole; corollas pink, blue, violet, yellow, or white.
....3 Stamens monadelphous; corollas 7-20 mm long.
......4 Corollas pink
......4 Corollas yellow.
........5 Plants glandular-punctate.
........5 Plants eglandular
..........6 Calyx deeply 5-lobed; upright (rarely sprawling) annual herbs, mostly 8-20 dm tall
..........6 Calyx with the upper 4 lobes connate; decumbent perennial herbs, the stems to 5 dm long
....3 Stamens diadelphous (9 and 1); corollas 3-16 mm long.
............ 7 Foliage punctate-glandular; corollas blue, violet, or white.
............ ..8 Fruit not beaked; corollas 4.5-8 mm long
............ ..8 Fruit beaked, the beak 3-7 mm long; corollas 7-12 mm long
............ 7 Foliage eglandular; corollas purple, pink, red, or white.
............ ....9 Lateral veins of each leaflet lateral veins neatly straight and parallel to one another; leaflets entire; [tribe Desmodieae]
............ ....9 Lateral veins of each leaflet complicatedly and irregularly arrayed; leaflets denticulate; [tribe Trifolieae]

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

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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
....3 Legumes straight or nearly so, never tuberculate or prickly; stems terete or flattened (2-angled) towards the tip
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]
........5 Flowers papilionaceous; stamens 10, diadelphous or monadelphous.
..........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, indeciscent; [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.
............ ........11 Stipels absent on the petiolules of mature leaflets; stamens monadelphous.
............ ..........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]
............ ........11 Stipels present, persistent; stamens diadelphous (9 and 1).
............ ............ 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 inconspicuous; [soy beans]
............ ............ ..14 Keel of corolla not coiled; stipules conspicuous, persistent, striate; [bush green beans or lima beans]
............ ......10 Leaflet blades smaller, all on a plant < 5 cm long.
............ ............ ....15 Stipels present, persistent.
............ ............ ......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)
............ ............ ....15 Stipels absent on the petiolules of mature leaflets.
............ ............ ........17 Fruits dehiscent, a legume with 2 or more seeds.
............ ............ ..........18 Terminal leaflet very similar in size as the 2 lateral leaflets; banner petal prominently striate-veined
............ ............ ..........18 Terminal leaflet 2× or more as long as the 2 lateral leaflets; banner petal evenly colored
............ ............ ........17 Fruits indehiscent: either 1-seeded, or a loment with 2 or more one-seeded (indehiscent) segments.
............ ............ ............ 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 a loment, with 1-3 segments; terminal leaflets 3-10 cm long, 1-1.5× as long as wide; stamens monadelphous
............ ............ ............ ..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/or calyces glandular-punctate; corollas yellow.
............ ............ ............ ....21 Leaves, stems, and calyces lacking punctate glands; corollas yellow, pink, purplish, white, red, blue.
............ ............ ............ ......22 Leaflet blades smaller, all on a plant < 5 cm long.
............ ............ ............ ........23 Stipels absent on the petiolules of mature leaflets.
............ ............ ............ ..........24 Fruit a loment of 2 segments, the terminal segment fertile, the lower segment either sterile or fertile; corollas lemon to orangy yellow
............ ............ ............ ..........24 Fruit 1-seeded; corollas pink-purplish to white, or bronze to brick-red.
............ ............ ............ ............ 25 Corollas pink-purplish to white
............ ............ ............ ............ 25 Corollas bronze to brick-red
............ ............ ............ ........23 Stipels present, persistent (minute in Amphicarpaea).
............ ............ ............ ............ ..26 Fruit a loment (separating into single-seeded segments), uncinulate (with hooked hairs, the fruits attaching to hairs or clothes as 'stick-tights').
............ ............ ............ ............ ....27 Flowers in axillary or terminal racemes; leaflets rotund, broadly ovate, broadly elliptic, or narrowly elliptic, the larger > 1 cm long.
............ ............ ............ ............ ....27 Flowers in axillary clusters; leaflets broadly obovate, 0.5-1 cm long
............ ............ ............ ............ ..26 Fruit a legume, dehiscent (at least tardily), unsegmented, and with 2+ seeds.
............ ............ ............ ............ ......28 Flowers resupinate (the pedicel twisted 180 degrees), the banner 2.5-5.5 cm long and positioned lowermost.
............ ............ ............ ............ ........29 Calyx lobes equal to or longer than the calyx tube; fruits 3-5 mm wide
............ ............ ............ ............ ........29 Calyx lobes shorter than the calyx tube; fruits 5-8 mm wide
............ ............ ............ ............ ......28 Flowers not resupinate, the banner 0.7-2.5 cm long and positioned uppermost.
............ ............ ............ ............ ..........30 Stipules caducous
............ ............ ............ ............ ..........30 Stipules persistent, sometimes conspicuous, sometimes striate.
............ ............ ............ ............ ............ 31 Keel petal and the included style straight to gently upcurved; stems very slender, < 0.75 mm in diameter
............ ............ ............ ............ ............ 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 pink to lavender (or whitish); corolla keel usually somewhat twisted, asymmetrical; [widespread in our region]
............ ............ ............ ............ ............ ....33 Corollas yellow; corolla keel symmetrical; [mainly outer Coastal Plain]
............ ............ ............ ............ ............ ..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 long, the flowers borne in clusters on a raceme axis shorter than the peduncle; plants glabrate to villous, the hairs not hooked
............ ............ ............ ............ ............ ......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)
............ ............ ............ ......22 Leaflet blades large, at least the largest terminal leaflets on a plant > 5 cm long.
............ ............ ............ ............ ............ ........35 Stipels absent on the petiolules of mature leaflets; stamens monadelphous
............ ............ ............ ............ ............ ........35 Stipels present, persistent (minute in Amphicarpaea); stamens diadelphous (9 and 1) or monadelphous (Pueraria).
............ ............ ............ ............ ............ ..........36 Stamens monadelphous; robust herbaceous vine with stems to 30 m long; flowers purple, when fresh smelling like artificial grape flavoring.
............ ............ ............ ............ ............ ..........36 Stamens diadelphous (9 and 1); herbacous vines with stems usually < 5 m long; flowers various in color, not 'grapy' in odor.
............ ............ ............ ............ ............ ............ 37 Flowers resupinate (the pedicel twisted 180 degrees), the banner (standard) petal lowermost; banner (standard) 25-50 mm long, much larger than the other petals.
............ ............ ............ ............ ............ ............ ..38 Calyx lobes equal to or longer than the calyx tube; fruits 3-5 mm wide
............ ............ ............ ............ ............ ............ ..38 Calyx lobes shorter than the calyx tube; fruits 5-8 mm wide
............ ............ ............ ............ ............ ............ 37 Flowers not resupinate, the banner (standard) uppermost; banner (standard) < 25 mm long, or if up to 30 mm then not much llonger than the other petals.
............ ............ ............ ............ ............ ............ ....39 Fruit a loment (separating into single-seeded segments), uncinulate (with hooked hairs, the fruits attaching to hairs or clothes as 'stick-tights')
............ ............ ............ ............ ............ ............ ....39 Fruit a several- to many-seeded legume, glabrous to hairy (but not uncinulate).
............ ............ ............ ............ ............ ............ ......40 Keel incurved < 90 (-120) degrees; style glabrous or pubescent.
............ ............ ............ ............ ............ ............ ........41 Stipules inconspicuous or obsolescent.
............ ............ ............ ............ ............ ............ ..........42 Leaflets coarsely toothed; roots tuberous
............ ............ ............ ............ ............ ............ ..........42 Leaflets with entire margins (sometimes with 1-2 rounded lobes); roots slender
............ ............ ............ ............ ............ ............ ............ 43 Corolla 3-4 cm long; fruits constricted between the seeds; fruits with stinging hairs
............ ............ ............ ............ ............ ............ ............ 43 Corolla < 2 cm long; fruits constricted or not; fruits glabrous or hairy, the hairs not stinging.
............ ............ ............ ............ ............ ............ ............ ..44 Bracteoles below the calyx persistent; ventral suture of the fruit bumpy-nodose; style bearded
............ ............ ............ ............ ............ ............ ............ ..44 Bracteoles caducous; ventral suture of the fruit not bumpy-nodose; style glabrous.
............ ............ ............ ............ ............ ............ ............ ....45 Leaflets (2-) 4-8 cm long, 0.8-1.5 cm wide, 5-6× as long as wide; leaflet apices acute to obtuse; fruits not flanged or winged
............ ............ ............ ............ ............ ............ ............ ....45 Leaflets 6-14 cm long, 4-10 cm wide, 1-1.3× as long as wide; leaflet apices strongly acuminate; fruits with a flange or wing along the ventral suture
............ ............ ............ ............ ............ ............ ........41 Stipules persistent and conspicuous.
............ ............ ............ ............ ............ ............ ............ ......46 Legume quadrangular in ×-section, 4-winged
............ ............ ............ ............ ............ ............ ............ ......46 Legume circular, elliptic, or oblong in ×-section, not winged.
............ ............ ............ ............ ............ ............ ............ ........47 Flowers clustered 3 or more at the inflorescence nodes; upper calyx lobes fused.
............ ............ ............ ............ ............ ............ ............ ........47 Flowers arrayed differently; upper calyx lobes separate.
............ ............ ............ ............ ............ ............ ............ ..........48 Keel petal and the included style straight to gently upcurved; stems very slender, < 0.75 mm in diameter
............ ............ ............ ............ ............ ............ ............ ..........48 Keel petal and the included style strongly curved upwards 90-180 degrees; stems slender to thicker, > 0.75 mm in diameter
............ ............ ............ ............ ............ ............ ......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.
............ ............ ............ ............ ............ ............ ............ ............ 49 Plants uncinulate pubescent (use 20× magnification, or touch the plant for the 'tacky' feel)
............ ............ ............ ............ ............ ............ ............ ............ 49 Plants glabrate to villous, the hairs not hooked.
............ ............ ............ ............ ............ ............ ............ ............ ..50 Keel petal and the included style strongly curved upwards 90-180 degrees
............ ............ ............ ............ ............ ............ ............ ............ ....51 Corolla keel symmetrical; [mainly outer Coastal Plain]
............ ............ ............ ............ ............ ............ ............ ............ ....51 Corolla keel usually somewhat twisted, asymmetrical; [widespread in our region]
............ ............ ............ ............ ............ ............ ............ ............ ..50 Keel petal and the included style even more extensively coiled (asymmetrically and spirally) in towards the flower center.
............ ............ ............ ............ ............ ............ ............ ............ ......52 Corolla 2.5-4 cm long, the wings about as long as the other petals; leaflets not lobed
............ ............ ............ ............ ............ ............ ............ ............ ......52 Corolla 1.5-2 cm long, the wing petals longer than the other petals; leaflets lobed