These are sprouts from a very old tree. They are doing tremendously so far. We dug up a few and planted them in the yard. The rest, I have in pots. Pecan trees have both the male and female flowers on the same tree. They are wind-pollinated. There is also some cross-pollination going on. Self-pollinating trees don't produce nearly as much. This tree produces a lot of nuts.
A little more insight.