Mora megistosperma
Mora megistosperma is a species of rainforest tree in the  Bean Family (Leguminosae, or Fabaceae and in the Cassia subfamily Caesalpinioideae. It is commonly called Mora or Mangle Nato It is found in Costa Rica, Panama Colombia and Ecuador. It grows 147 feet (45 meters) in height and up to thirteen feet (4 meters) diameter at breast height (D.B.H.). It is most noted for producing the largest seeds of any Dicot plant (kidney-shaped typical of the family); and  up to 7 inches (18 cm) long by six inches (15 cm) wide, and up to four inches (ten cm) thick. and can weigh up to 2.2 pounds (1000 grams). and is exceeded only by Lodoicea and Cocos nucifera var. gigantea. The white flowers are in little spikes about  five inches (twelve centimeters) long. The leaves are paripinnate with just two pairs of ovate or oblong leaflets, each leaflet up to seven inches (18 centimeters) long. References

External links
 Blog with photograph of the seed: 

Caesalpinioideae