Keep it simple.
Books used to be my method of identification. Taking with me an old Collins gem. When I got home I would get out a large A4 book with better pictures and descriptions BUT less mushrooms in it.
I now use apps (as well) they are not perfect but they have advantages. They allow you to describe different parts of the mushroom and therefore eliminating mushrooms as you go through the app.
Despite what people think it's quite hard to make mistake mushroom picking. Firstly if you cannot identity then don't eat it! Also there is huge amount of exaggeration over the dangers of mushroom picking. Poison nowadays is defined as anything that has a detrimental affect on your health, no matter how minor or short term. This is a rough way of looking at it.
1/ Edible (yummy)
2/ inedible: looks like crap, taste like crap...may even be crap!
3/ Suspicious: No agreement on. May be like Asparagus ie some peoples pee stinks after eating it, others peoples does not.
4/ Poisonous: A mild stomach ache
5/ Very poisonous: Bad stomach ache no known deaths but possible if you were in poor medical condition.
6/ Welcome to death: 8 hours of extreme stomach ache 8 hours of relief (the poison is still attacking your liver\kidneys) followed by 8 hours of extreme pain.....dead. If you are treated within 24 hours and assuming reasonable medical condition you will still need a kidney/liver transplant. There is only 3 of these. Note when I use stomach ache it's just being used for comparison. Fly Agaric for instance, the mushrooms they give Reindeer is an Hallucinogenic. It's the red "toadstool"
Another thing worth noting: There is no scientific difference between a toadstool and mushroom. Nor is there agreement on what is and isn't a toadstool. There are far more poisonous mushrooms than toadstools, although not proportionally.
It should also be noted that the difference between two mushrooms which grow in the same place which you are warned about making a mistake over are invariably significantly different.
The fairy ring champignon and a mushroom called clitocybe....something like that! The mistake is made in certain weather conditions when the caps maybe the same color. The actual differences, ignoring cap color is huge. You have to be stupid or ignorant to mix the two up. Assuming your not the former putting some effort in will protect you from mistakes, Obvious mistakes.
The exception and where most poisonings occur is between the field mushroom and the yellow stainer. Now these do look like but they don't grow in the same place, Stainer prefers wood margins (inside). When cut it is supposed to go yellow along the cut, personally I don't see this But the foot always has very bright yellow splodges. It is also supposed to turn into a yellow mush when cooked.
Edit..it doesn't taste like the field mushroom either.
If you want to take up mushroom (fungi) picking but don't want to spend your time worrying, then follow these rules.
Specialise. The most obvious being field and fairy ring. The latter is in abundance spring to autumn. Remove the stem as it is very fibrous. I have yet to try dehydrating it but this is the most obvious one for dehydrating. Stuff in small jar and top up with oil adding whatever takes your fancy garlic being the obvious one. I do this with tomatoes every year and wait one year before using.
Don't mix them and if it is a new mushroom keep two back one for the A&E doctor and one for the coroner!!
Also note locations and check the same places every year.
You could of course specialise in mushrooms which you cannot make a mistake with the puffballs and ink cap for instance.
Personally I think people should avoid all wild mushrooms.....and leave them for me!
