Trio of Agaricus Species. Poison, anyone?

KevinForaging, From The Wild, Mushrooms4 Comments

This morning my two daughters were looking for an adventure, which, well, turned out to be more mushroom hunting. Surprise! Yeah, not. Well we found a pile. 3kg worth. That’s about 7 paper lunch bags full. As I started to clean them up for drying though, I noticed they were far from all the same. I had been doing some homework on this genus, and knew that I should check for obviously yellow staining near the base of the stem when it’s broken – Agaricus Xanthodermus is what folks would call ‘poisonous‘. Not ‘you’ll die on the spot‘ kind of poisonous in this case, but more like ‘if you eat some your GI tract might not like you very much, in a very severe way‘ kind of poisonous. So a-stem-cutting I went, and found a very significant portion of what we’d picked had distinctively yellow bruising. Many Agaricus species bruise yellowish, apparently, but this one far more obviously so. See photo below. The second trait I notice was they really didn’t smell that nice. As in, they smelled nasty. Mushroom resources online suggest: phenolic. I’d describe this as ‘stale oil, bitter, chemical, kreosote-esque’. All around, not so nice. For a moment I was saddened by my loss of mushrooms, but then giddy with having learned something quite important. The lot of what I’m figuring is my first Agaricus Xanthodermus is shown below, piled up in my compost bucket. If you live just west of the University and these look familiar, it’s probably because they’re from your boulevard. Don’t worry, my girls and I didn’t eat them.

By far a bigger take-away for me than seeing first-hand some solid yellow staining was the smell. I was suddenly very grateful for my wine nerd-ness. The three mushrooms in the top left photo smelled vastly differently. I’m pretty sure I could have sorted those 3 kinds out with a blind fold on. The bottom right pinky one is the stale chemical stinky, yellow staining guy. Rather revolting, and apparently that stink saves many from downing too many of the wrong kind. The top I’m guessing is Agaricus Campestris which is what I’ve had in my fridge the past few days. It smells lovely, mushroomy, like a bowl of mushroom soup, begging for crackers. And the lower left was a surprise. Obvious, smack in the face sweet, clearly articulated anise vibe. I had just read that this is an indicator of Agaricus Arvensis, or ‘horse mushroom’. It was far more round than the flatter Campestris, and smelled lovely. Thankfully, Arvensis is a choice keeper in the edible category. Of course, that assumes my IDs are right, and this is all still pretty new to me. I’m including a photo at the bottom of a group of what I think are Agaricus Arvensis – whatever they are: the anise smelling ones.

So my takeaway for the day: keep harvesting agaricus like mad, but give them a thoughtful sniff before choosing to bring home or not. This genus obviously varies widely on aromatics, and quite plainly, even if not poisonous, I’m not interested in nasty smelling mushrooms for the kitchen. Yes, I’m going mushroom hunting again tomorrow, but I’ll give you a break with a ‘From Local Farms‘ episode.

As always, my disclaimer. I’m still very green at this. I will correct the above if I’m corrected and/or learn better down the road. I am not a mushroom guide, book, or substitute for your own judgement, this is only me journalling my adventures while learning about them. So there.

4 Comments on “Trio of Agaricus Species. Poison, anyone?”

  1. A Canadian Foodie

    You must have just posted this. I am just catching up. I think you are earning the coveted title of “The Nose”… as you know the master perfume sniffer is known as, and has undergone years and years of training in France. It does appear that your years of “nosing around” is definitely paying off for you. Clearly, you are a quick study – and when into something – INTO it. I love that!

  2. Josh

    “So my takeaway for the day: keep harvesting agaricus like mad, but give them a thoughtful sniff before choosing to bring home or not.”

    Just a somewhat belated thought on this. Is it possible that the smell is less species specific and more to do with what they were growing on?

  3. Margy

    Smelling agaricus is the main way I can tell if it’s a good kind (campestris, for example) or one of the very common stinky ones. I nick the base of the mushroom and see if it’s yellow and also sniff it for that “library paste” “phenilic” smell. Sometimes I have to do a lot of sniffing to tell; sometimes it’s not obvious. But campestris will always smell like a lovely mushroom : unmistakeable! But sometimes an Agaricus will not smell like much at all. In that case it usually turns out to be a bad one (after more careful, repeated smelling).

  4. Doug

    I recently found some A. Californicus, a milder version from the xantho tribe. Although they were supposed to stain yellow slightly, somebody forgot to tell the mushrooms and they absolutely didn’t stain at all no matter what I did to them. After crushing both caps and stem bases and having a nice smell, I cooked them up and ate several meals but they had a flavor that was ‘off’ and not enjoyable. Fortunately I turned out to be one of the lucky few that do not suffer wth ill effects from this toxin, so only felt a little funny, gastrically speaking.

    After harvesting a bumper crop for a feast, thinking I was just doing a bad job cooking them, I tried 4 different ways and all of them tasted bad. Back to the internet for hours and hours until I decided to chemically test these before eating more.

    Cutting a stem in half lengthwise and spraying a bit of Lysol on them turned them bright yellow in less than a minute!

    So the lesson is: don’t just depend on smell or staining, you can still get a bad batch of agaricus into your skillet unless you hit the stems with a bit of Lysol. If you do get some in your skillet, they will not taste good, so trust your instincts and don’t assume you cooked them wrong.

    Epilog: I tossed my beautiful harvest out for the deer and slugs and bugs. My stomach and gut rumbled and I got a little flushed, but all was ok in spite of eating so many… whew!

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