I find it hard to imagine anyone relying on an app to determine whether or not a wild mushroom is edible or not. The poisonous mushrooms (particularly the wide

I find it hard to imagine anyone relying on an app to determine whether or not a wild mushroom is edible or not. The poisonous mushrooms (particularly the widely distributed and complex Amanita types) have some of the most insidious biological toxins known, in particular alpha-amanitin, which has a really nasty delayed-action effect: https://en.wikipedia.org/wiki/%CE%91-Amanitin https://en.wikipedia.org/wiki/%CE%91-Amanitin It's mode of action is so unique (binds RNA polymerase, so destroying liver and kidney protein synthesis and leading to widespread cell death) that it's used in molecular biology labs for the study of protein synthesis. Maybe some of the more obvious edible types (boletes, chantrelles, some others) are fairly easy to identify, but even there they have stomach-upset causing relatives. Anything even vaguely similar to Amanita should be viewed with caution (there are closely similar edible types, no thanks). A few good books with lots of pictures, close attention to things like spore prints, going with someone with a lot of experience, that's the best introduction.