Meet the "Pecan" Tree - Carya illinoensis. A large domed tree, native to Floodplains and River Valleys in the Southeast and Central Eastern US. It's leaves can get up to 20 inches long, and are made up of 11-17 opposite, toothed leaflets. The flowers are a greenish color, the males have slender catkins in cluster of 3's, while females have clusters of 2-10 on the same twig.
Image Citation (Pecan Leaves): Paul Wray, Iowa State University, Bugwood.org
The Pecan is a member of the Hickory family, a small species with just 11 members in the Eastern US, 1 other in Mexico and 2 in South China. The Hickory family is part of the larger Walnut family-they have similar pinnate leaves and large fruits but differ in wingnuts, flower and branching structures. The timber is very tough, slightly elastic and shock resistant. They are not easily grown as the seeds can only be used when fresh, they also do not transplant well.
Image Citation (Pecan Plantation): Howard F. Schwartz, Colorado State University, Bugwood.org
The Pecan is widely planting throughout the United States for it's nuts, often in plantations. It flowers in the early spring and produces fruit in the fall. A pecan, like the fruit of all other members of the hickory genus, is not truly a nut, but is technically a drupe, a fruit with a single stone or pit, surrounded by a husk. The seeds of the pecan are edible, with a rich, buttery flavor. They can be eaten fresh or used in cooking, particularly in sweet desserts. Int he photo below you will see a shaker harvesting Pecan nuts from the tree.
Image Citation (Shaker Harvesting Pecan Nuts): Brad Haire, University of Georgia, Bugwood.org