I do a lot of mushroom hunting and have done so all my life.
The only really deadly ones are:
Destroying Angel,
http://en.wikipedia.org/wiki/Destroying_angel(and http://en.wikipedia.org/wiki/Amanita_phalloides which is similar, but olive green). These are the most poisonous mushrooms known, and one specimen may well be lethal. There is no antidote! White and olive green mushrooms should be avoided altogether by amateurs. Note the frightening resemblance with the usual Champingon
http://en.wikipedia.org/wiki/Agaricus !
Lethal webcaps,
http://en.wikipedia.org/wiki/Lethal_webcaps There are hundreds of species of webcaps, some of them delicious, some of them deadly poisonous. Webcaps are avoided even by experts.
Any mushrooms that show the slightest resemblance with these above should be avoided! Don't pick juvenile mushrooms as they can be difficult to identify safely!
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Now for the good part: The most delicious mushrooms can not be confused with poisonous ones.
The easiest ones to start with (and that never can be confused with poisonous species):
Chanterelles,
http://en.wikipedia.org/wiki/Chanterelle (if you can find them in the UK, I don't know, most likely in Scotland perhaps)
Porcini,
http://en.wikipedia.org/wiki/Boletus_edulis
Suillus Luteus (Butter Bolete?),
http://en.wikipedia.org/wiki/Suillus_luteus
(As Ryan C wrote, boletes are identified by a spongy layer instead of gills under the cap. There are no poisonous boletes, although some taste utterly bitter. Unfortunately, boletes are often affected by larvae. These must be discarded)
Puffballs,
http://en.wikipedia.org/wiki/Puffball when young and firm. Cut them in half lengthwise so you can make sure that there is no inner structure at all.
Hedgehog Mushroom,
http://en.wikipedia.org/wiki/Hydnum_repandum can not be confused with anything else - for once Wikipedia is wrong here, the Sarcodon Scabrosus can hardly be confused with it. The latter is dark brown!
For the hedonist:
False Morel,
http://en.wikipedia.org/wiki/Gyromitra_esculenta is proven carcinogenic. Consumption is said to be comparative to tobacco smoking. It's clearly acutely poisonous in its raw state and must be parboiled twice for 5 min each in new water, which is discarded, before further preparation. Make sure the kitchen is well ventilated during parboiling since the steam is toxic. When correctly prepared, some (like me) consider it the most delicious mushroom in the world. It's our equivalent of the Japanes Fugu or pufferfish. Sale of it is banned in many European countries (in Sweden it can only be sold to restaurants).
I think that will do for a start.
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All mushrooms should be cleaned with a brush, halved to make sure there are no larvae and very quickly rinsed. Don't rinse if it's unnecessary. It makes them slimy. Then cooked. Don't eat them raw - it's not dangerous except for the false morel but your stomach will probably disapprove. Hedgehog mushrooms and false morels should always be parboiled in salted water for 5 minutes. Other species can be sauteed or otherwise cooked directly.
Most mushrooms can be dried. Exceptions include the chanterelle. Puffballs and porcini are especially delicious when sliced thinly and dried. If you plan on drying false morels, the room should be ventilated as they emit toxic gases.
Mushrooms can also be frozen. The best method is to boil them with no extra liquid until all water has evaporated before freezing. You'll be surprised how little is left!
There are numerous recipes for pickled mushrooms.
Mushroom hunting is a rewarding hobby. You get exercise, fresh air, knowledge and food!
(and mosquito bites and ticks etc
). Please try it and good luck!
Just remember the old saying "
There are old mushroom hunters and bold mushroom hunters, but no old and bold mushroom hunters".
I'm sure there are mushroom associations where you live. They are usually very hepful as a first step.