>>4391411Aesculus, aka horse chestnut. I started cultivating them for fun last year, those are 2023 seedlings as they looked in January this year. The tallest are now over 3 feet tall and hibernating (basically look like bare sticks). I just planted (sowed?) a whole bunch of this year's seeds earlier this week.
When I was a kid we used to collect them compulsively and build stick figures by poking matches or sticks into them (acorns were used also). Or just play with them as is. That was back in Europe, where the aesculus genus trees are much taller, but the nuts themselves are smaller. Also the skins are spiky.
I don't think anyone knows or cares about them in the US though (at least in California here).