>>1097553You don't have to know every plant, just learn how to identify some genuses; Brassicas (all parts), Grass seeds and Rubus and Vaccinium fruits are all always edible, and they grow all over the world. Once you know what those four genuses look like, you've got 80% of the plants you'll want to eat. Just stay away from Solanum and Vitaceae, pretty much any wild plant that looks like a tomato or grape is going to kill you.