I’ve seen a bunch of mushrooms popping up lately. They’re the typical white flat top kind that are around the size of a persons open hand. I’m in Maryland and these tend to pop up n th middle of the lawn. How can I tell if these are safe to eat?
I’d like to use them in some soups & stews. How can I be sure?
I’ve always heard that its a very bad idea to play “roulette” with mushrooms you see growing around anywhere.
Its either impossible or really hard for the average joe to determine if your mushrooms are poisonous or not.
Definitely not something that you want to do without being an expert, this just happened a couple of weeks ago:
First, find an old mycologist who lives in your area. Both of those qualifications are important: Mushroom species may vary from place to place, and a young mycologist is often just one who hasn’t managed to kill himself yet. Then, bring him to your house and ask if a mushroom is safe to eat. If he says yes, then let him eat half of it. Wait a few days. If he’s still alive, that particular mushroom is safe to eat, and you can have the other half. Then, ask him about the second mushroom, and repeat.
IME it’s as hard to make that decision over the internet as it is to get medical advice on the SDMB. We have a patch of mushrooms that keeps popping up in the backyard. I have no interest in eating them, but I wanted to know if they where dangerous for my dogs. I never even got a good answer to that. What it came down to is that even if you could describe them really well in writing (a hell of a lot better then ‘white hand sided mushrooms’) there’s still a lot of mushrooms that are similar. You really need someone who knows what they’re talking about to come and look at them.
There are no reliable ‘rules of thumb’ when it comes to determining the safety of fungi for the table; there are ‘folk wisdom’ identification methods determining edibility based on whether it turns black in contact with silver, whether is it being eaten by other animals, etc. They are all unreliable. The only safe method is positive identification of species based on comprehensive examination of the fruiting body’s appearance, smell, texture, habitat, season, spore print and taste (taste can be used diagnostically for even the most poisonous species, as long as only a small piece is tasted and spat out afterwards, but I don’t recommend this and I don’t think many mycologists use it routinely).
Having said all that, some common species are very easy to positively identify, and very difficult to mistake for anything poisonous, but positive identification is the only way.
My grandmother used to collect and eat wild mushrooms, but my mother, her daughter, refused to eat them. I don’t recall her ever picking the “toadstools” that grew in the yard though and I seem to remember her saying that they weren’t edible, although I don’t know if that was because they were toxic, or just tasted bad.
BTW, my granny died of natural causes in her late 80’s.
Here’s a site: Recent News Releases — Extension and Ag Research News
An acquantance of mine died from liver failure last year after picking wild mushrooms and eating them. I recommend against trying them.
But I know nothing about mushrooms.
That is one badass name for a mushroom! Bandname anyone?
How about the big yellow ones that can grow right up through an asphalt driveway? Anything that strong can’t be good for you.
Be careful you don’t get Roomis Igloomis.
You think that’s impressive? Check out this:
The power of fungus commands you? 
I just saw this movie, too. You’re hilarious.
Another recommendation to please never eat mushrooms you just find! People die in India all the time from eating mushrooms. Are you starving or something? Mushrooms arne’t that expensive from the grocery store!
Is that you, Old Dr. Young? Or Young Dr. Young?
Counterpoint to the above; if you get the chance to go out foraging for wild mushrooms, accompanied by someone who really knows what they are looking for, go for it! - wild mushrooms are nearly always nicer than anything you can buy in the shops. In Northern Europe, there are a couple of dozen really good edible species for which positive identification is really easy to learn. The situation in America and elsewhere may not be so convenient; I don’t know.
Most likely based on your very vague description, they are some species of Agaricus. That genus are widespread saprobes that pop up a lot on lawns and can get decent sized. Again, most likely, they are in a section of the genus called the Xanthodermati and are NOT good to eat. If they have a “phenolic” odor and the base of the stipe or the cap develops a slight ( or bright ) yellow stain when you score it with a fingernail or better yet put a drop of KOH on them, that would be at least a partial confirmation of that.
But that’s just most likely and that’s not a very likely most likely, if you get my meaning ( i.e. the number of possibilities are large ). Mangetout has it exactly right - avoid them unless absolutely confirmed by someone qualified. And even if confirmed as edible ( and oddly enough some good edibles do pop up on lawns, including other sections of Agaricus ), I’d treat them with caution. Because A) lawns are often treated with not-so-good-to-eat chemicals and B) first exposure to new species of even ostensibly edible mushrooms can cause an adverse reaction ( usually an upset tummy ) in certain individuals.
Please avoid them.
You guys are making this to complicated. The easy way to tell edible mushrooms is to eat only the ones you find in the produce section of the grocery. 
David Simmons, now I wants me some Portabello mushies.
Mmm…portabello. drools
You saw that movie, too? What a coincidence… Because I didn’t, and have no clue what movie you’re talking about.
There’s at least one edible species in America which is easy to positively identify: the morel. Apparently they’re highly prized, going for something like $70 a pound, but I didn’t like them at all, when I tried them. At the right time of year, you can find enough in an afternoon in the forest to make a small side dish with dinner.
