Maxperson
Morkus from Orkus
1) It's lore, so by RAW it's Nature. So it is true.That's not true. Knowing if a mushroom is poisonous or not comes under foraging. Obviously. Since if I cannot tell between harmful and beneficial plants, how can I forage for food? Nature tells you exactly what kind of mushroom is and what family it belongs to and all the academic knowledge around that mushroom, but, Survival absolutely will tell you if it's safe to eat.
2) You can just forage and hunt stuff that has no poisonous versions. You don't HAVE to get mushrooms to survive.