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........5 Pinna pairs 2-8 per leaf; leaflet pairs 6-20 per pinna; leaflets 1-6 mm long; inflorescence spherical, yellow to orange
..........6 Leaves with 4-8 pairs of pinnae; each pinna with 15-20 pairs of leaflets; petiolar gland elliptic; stipular spines often basally fused; leaflets reticulate below
..........6 Leaves with 2-4 (-7) pairs of pinnae; each pinna with 9-20 pairs of leaflets; petiolar gland circular; stipular spines not basally fused; leaflets with or without apparent secondary venation, but not reticulate.
............ 7 Peduncle with bracts near the midpoint (or a nodal bump visible if they have fallen)
............ 7 Peduncle lacking bracts or with bracts immediately subtending the head.
............ ..8 Mature leaflets 4-5 (-6) mm long, with secondary veins apparent on the lower surface; [in our area from e. GA south through FL peninsula]
............ ..8 Mature leaflets 1.5-4 (-5) mm long, with secondary veins not apparent on the lower surface; [FL peninsula and panhandle west to TX and beyond]
............ ....9 Mature leaflets 2.5-4 (-5) mm long; petiole usually pubescent; peduncles lacking glands; [FL panhandle west to TX and beyond]
............ ....9 Mature leaflets 1.5-3.5 mm long; petiole glabrous; peduncles with tiny, red glands (use 10× magnification) (these deciduous and absent as the peduncle ages); [FL peninsula or s. TX]
............ ......10 Mature leaflets ca. 3 mm long; fruit valves velvety pubescent when young, becoming glabrescent; [s. TX]