Very tasty, are green elm seeds.
Pic: Elm branch with green seeds. Refreshing with a hint of nut, that's the best way to describe elm (Ulmus spp.) seeds. It's one of the trees that I'd really like to have growing near the house, just so I'd be able to raid it in early summer, when it's full of tasty seeds.
I wouldn't boil them up, but if you have a tree that you can raid unhampered, go ahead and pick a couple pints. I'd freeze the things; they don't taste like you could dry them. Add to salads or just nibble whenever you want.