hickory trees from other trees by their "peeling off" bark, flat-wide leaves, and big green nuts. Not to mention the cracked-open hulls strewn about the ground beneath the trees. When the nuts are ripe, the hulls open up like flowers and fall to the ground.
The nuts are easily cracked open with a hammer and very tasty. Great busy-work for little ones; my sister and I would spend hours cracking nuts out in the shop while my dad worked on farm machinery. Of course, the nuts were so good that we ate everything we cracked.
In addition to eating, the hulls can apparently be used for smoking, like the chips you buy. I have not tried this yet, as I don't have a smoker, but it's definitely on my ever-growing list of things to try.