Mockernut Hickory.  Carya tomentosa.  There are lots of different Hickory trees, but I'm fairly sure most of the ones in my yard are Mockernut Hickory.  

 

They are medium to tall deciduous trees.  The best time to spot them is in the fall, when they turn golden yellow.  Otherwise, if they are in your yard, you know by skidding on the nuts underfoot, and new shoots coming up where the squirrels have buried them.

 

Further inspection shows that the leaves generally have 7 - 9 leaflets, and the undersides and twigs are pale orange-brown and hairy.  The nuts are ball or egg shaped with a thick husk not splitting to the base.  

 

I've read that the nuts are edible, but I've never been THAT hungry.

 

I'll post another picture of Hickory in the fall when they are in their glory.

 

 

HAPPY GARDENING!!