Common Name(s): Argentine Osage Orange, FusticPerhaps it's Curupay? It surpasses hickory in some measures:
Curupay
Janka Hardness: 3,630 lbf (16,150 N)
Modulus of Rupture: 28,010 lbf/in2 (193.2 MPa)
Elastic Modulus: 2,617,000 lbf/in2 (18.04 GPa)
Crushing Strength: 13,700 lbf/in2 (94.4 MPa)
http://www.wood-database.com/curupay/
Shagbark Hickory
Janka Hardness: 1,880 lbf (8,360 N)
Modulus of Rupture: 20,200 lbf/in2 (139.3 MPa)
Elastic Modulus: 2,160,000 lbf/in2 (14.90 GPa)
Crushing Strength: 9,210 lbf/in2 (63.5 MPa)
http://www.wood-database.com/shagbark-hickory/
Or perhaps it's "Guayabi"? It's said to be preferred to hickory for ax handles (in Paraguay, at least).
from Consular Reports, 1896
Is "Guayabi" the same as "Guayabo", whose Modulus of Rupture, Modulus of Elasticity, and Work to Prop. Limit, all surpass that of Hickory, as shown in the table linked below:
Report about wood testing program in Panama
Scientific Name: Maclura tinctoria (syn. Chlorophora tinctoria, Morus tinctoria)
Distribution: Tropical America (West Indies, Central and South America)
Tree Size: 60-80 ft (18-25 m) tall, 2-3 ft (.6-1.0 m) trunk diameter
Average Dried Weight: 57 lbs/ft3 (910 kg/m3)
Specific Gravity (Basic, 12% MC): .75, .91
Janka Hardness: 2,380 lbf (10,590 N)
Modulus of Rupture: 19,560 lbf/in2 (134.9 MPa)
Elastic Modulus: 2,160,000 lbf/in2 (14.90 GPa)
Crushing Strength: 11,710 lbf/in2 (80.8 MPa)
Shrinkage: Radial: 3.4%, Tangential: 5.4%, Volumetric: 7.8%, T/R Ratio: 1.6
Close? A little harder and heavier. Still flexible.