Greenthumb18 said:
I was thinking for people who grow mushrooms outdoors in logs instead of mushroom kits, they would have to know how to distinguish the edible mushrooms from the poisonous ones, right? It would be scary to grow mushrooms to find out their were poisonous ones growing close by.
This is not realistically much of a problem for the commonly-sold-as-plugs species of mushroom. As free says, not much of anything poisonous grows on trees, and you pretty much know what a shiitake or oyster mushroom is *supposed* to look like anyhow.
The guy whose talk I heard also added to the above type response, when he was asked this question, that realistically either your plugs "take" in which case nothing is going to be growing on the log EXCEPT your shiitakes or whatever -- because their mycelia just take over and overwhelm anything else that might be trying to get started -- or your plugs die off and you get turkeytails (bracket fungi) which are nonpoisonous though inedible and not going to be mistaken for anything edible.
If you are sowing morel spores in the ground, hoping for morels in a few years, it would indeed be good to know what a morel looks like

and how to distinguish them from a false morel which in some cases can be somewhat poisonous -- but this is definitely not rocket science, morels are considered one of the "anyone can easily learn to identify them anywhere" fungi
Good luck, have fun,
Pat