are about 10,000 different kinds of mushrooms, but relatively
few -- perhaps about 100 -- are considered good to eat.
If you plan on eating a mushroom, you'd better be absolutely
sure of its identity, because 100 out of 10,000 isn't many
(1%). And some of those other 9.900 are poisonous. So be
very careful: check the identification with a truly knowledgeable
person before you heat up the frying pan.
edible fungi are illustrated in Chapter
18 of The Fifth Kingdom.
more detailed account can be found in the book and CDROM.