In a given region, there won't be thousands of species. And, within genera or even families, they'll look pretty similar. In the Northwest, it's so wet there are probably a couple dozens species at least. From what I've heard though, all psilocybin mushrooms will bruise blue-ish, due to the psilocybin presence. Of course, never eat anything you aren't 100% sure on. Even then, a small amount to check first would be very advisable.
I was just reading this in an article about mushroom explosion in the Vancouver area about a year ago: The BC Drug and Poison Control Information Centre received about 400 calls about exposure to wild mushrooms over the last two years. Most cases of serious illness were due to adults or teenagers eating poisonous mushrooms, either mistakenly harvested or used to try to “get high”.And the so-called “magic mushroom” (Psilocybe semilanceata) is frequently mistaken for its look-alike Galerina autumnalis, which is highly toxic and can be lethal if ingested.