Edibility
How to be 100% sure before you eat anything you picked.
Certain, or leave it
There is no "probably fine" in foraging. If you can't make a positive identification — not a guess, a match on every feature — you don't eat it.
What to check, every time
1 leaf shape and arrangement 2 stem, and whether it's hairy or hollow 3 flowers or fruit, if present 4 smell (crush a leaf) 5 habitat and season 6 cross-check in a second guide
The old universal edibility test
It exists, but it's a survival last resort, not a dinner plan. If you're relying on it, you've already picked the wrong plant. Learn your plants one at a time instead.