We have a couple of buckeye trees on our property. I think they're all Aesculus flava, the yellow buckeye. Most of them are tall and skinny and not much to look at because they're growing on a steep ravine in poor soil with little light. I'd love to have a large one closer to the house because I think they're beautiful trees with attractive flowers in the spring, but mostly it's the nuts that I adore.
In mid to late September the buckeye down by our mailbox begins dropping its seeds. Sometimes I find the entire fruit, a smooth yellowish-tan oblong capsule that reminds me of a russeted pear, on the ground. Other times I only find the nuts that have been released. Either way, I can't help but pick up every single one I can find.
The fresh nuts are a wonderfully glossy mahogany and chestnut color with a broad tan "eye" indicating where the nut was attached to its capsule during its development. They do remind you of a deer's eye, thus the name "buckeyes."
Buckeyes are perfectly smooth to the touch, although not always perfectly round. Some are flat on their sides from where they shared their capsule with another nut. All of them are hefty, just begging for a slingshot. Unfortunately the nuts will eventually lose their glossy sheen and gain a more wrinkled texture after they dry for a day or two.
Even the empty husks are interesting to look at.
By the second week of October the tree down by the mailbox has finished dropping its crop of nuts. I might find a few more this week if I kick the leaves around while I check the mailbox, but I've already picked up most of them.
I've heard that squirrels are one of the few animals that will eat the buckeye nuts. They're too bitter to the taste for most animals. The fruit capsules are high in tannic acid, much like walnut husks, and the nuts themselves are toxic and can only be eaten safely after they've been leached to remove the poisons. I've no plans to try them myself and just use them for fall decoration. (But I'm still thinking about getting a sling shot.....)