I'm not really sure if they are plant related, I kind of think they come from and animal but I really have no idea!
As you can see, they're tiny!
They each have one small hole, and are hollow, some of them still have dirt in the hole, that's why some look like they have a dark spot.
They're round but not perfectly round, kinda flat on the side with the hole.
They are hard as rocks! I mean I can't even crush one between my nails, it takes some serious force to break on!
I find them in losely scattered piles, on top of, and just beneath soil level.
They're very common, but hard to spot.