What Agaricus species?

[Sola]

Hi all,

Not that long ago I came across what I thought was an edible Agaricus species not far from home.

I thought I would try a simple non-sterile outdoor cultivation and to my surprise I've got dozens of these little beauties coming through on the pile.

I say little but some are 10-15cm across the cap, there is undoubtedly a veil and they stain yellow when cut.

There is a very earthy smell coming from them. Pink gills and the stalk is quite fibrous and tough.

They seem to be very happy growing in a combination of straw, manure and various types of wood.

They look the same as the mushrooms I've previously eaten and posted about so believe they are progeny from some I intentionally buried in the pile.

If you think you know what species this is I'd be very interested to know.

Thanks

Sola

[strangebrew]

If the top is squarish/blocky when young & they tend to grow in congregations, they're yellow stainers - A.xanthodermus.

When older they're often scaly brown or purple and the top has a sunken look about it.

Some people can eat them, I have in the past, but generally they don't taste that great.

P.S. The other stainer is the Horse mushroom but these are smooth, white and circular.

Edited June 6, 2011 by strangebrew

[Sola]

Thanks strangebrew, I think Agaricus xanthodermus may be the one.

They definitely grow in clumps and before they've fully opened their cap they have a somewhat square appearance.

I haven't seen purple but I have seen scaly brown textures.

I don't know the horse mushroom but I'll look into it.

Thanks again.

[strangebrew]

I'm certain they're xantho's, SA seems overrun with them. Unfortunately they tend to grow where the good'uns grow but just occasionally I get lucky with something decent. Horse mushrooms are really tasty btw.

[Sola]

Yep, now I've looked into it I'm sure too. I did eat them ITP with no bad reaction, they didn't even taste too bad but I guess it's a good lesson to check better than I did last time.

What's the species name of the horse mushrooms? Because after doing a little digging I found some pics of A. augustus, A. austrovinaceus and of course A. xanthodermus and think we have all of them here.

I'd like to try some horse mushrooms too. Have to keep my eye out.

[strangebrew]

Don't think A.augustus are in SA unfortunately.

Horse mushrooms are A. arvensis, they're solitary & have a "cogwheel" look about them underneath before the veil breaks.

In regards to the xantho's, I think the amount of phenol they contain is quite variable. Some have virtually no smell at all, so they're probably OK to eat if you're really keen.

P.S. Forget the purple. I was getting confused with some other evil looking Agaricus I've found recently that stain red.

[Sola]

Thanks for your help, I think these ones have less phenol but I think I'll just stick to the better tasting ones all the same.

I have found a few things here that aren't supposed to be in SA, both mycological and flora.

We do have a patch of as close to virgin scrub as it gets around here so luckily we have some real rarities.

But I may have been mis-identifying them so I'll have to keep up the posts of any unusual ones I find.

Some I've only ever seen once or twice I don't feel comfortable picking to get good pics for ID though as I don't want to jeopardise its survival.

I've taken in situ pics that unfortunately weren't sufficient for ID pruposes.

How could I take a specimen without having fear of damaging the local population?

[Distracted]

I'm certain they're xantho's, SA seems overrun with them. Unfortunately they tend to grow where the good'uns grow but just occasionally I get lucky with something decent. Horse mushrooms are really tasty btw.

 

You're not kidding about SA being overrun, i'm seeing the xantho's freaking everywhere! I haven't found a single edible field mushroom yet

[strangebrew]

Yeah they're popping up all over the place now even, whereas you're more likely to find the better ones whenever the weather's warmer, more humid, like in early autumn or spring but beware the xantho's will be there. They seem to have a much wider growth parameter temperature wise. I've heard they are a much more agressive species and really are taking over.

How could I take a specimen without having fear of damaging the local population?

As long as you give the cap a tap & cut the stem with a knife you should be right.

[Sola]

Awesome, thanks for that, I didn't want to reduce the already rare species.

Should have some interesting pics to show ITNF and yes they do seem more aggressive. I put several spores/ mushrooms in the outdoor pile.

They're definitely the ones that have taken over and fruited in record time. At least the soil should be improved.

[Undergrounder]

I'm definitely no expert when it comes to Agaricus, I've only ever eaten A. campestris, although I have seen my fair share of xanthos.

I was once told when distinguishing between Agaricus (ie: you're sure it's Agaricus to begin with) to follow your nose. Fragrance is the most important distinguishing factor, bruising/staining is second and cap shape/size/growing habit, etc. a distant third.

- If it smells pleasant and stains slightly yellow, it's a Horse mushroom (arvensis).

- If it stains yellow and has a strong, harsh, chemical/iodine smell, it's xanthodemus.

- And then the other two pleasant smelling edibles that don't stain yellow (augustus and campestris) are fairly obvious to tell apart by size alone. Augustus are large (10 - 25cm+), campestris (Field mushrooms) are small (5 - 10cm).

Which makes me think they were A. arvensis?

I just double checked my A.M. Young book and he doesn't mention that A. arvensis are solitary, in fact refers to them as growing in 'groups' and 'rings'. So if you believe him, that still fits with A. arvensis. I know xantho caps are quite flat and squarish when young, but I don't think you need to refer to cap shape to positively ID these. These caps are round enough to fit with arvensis. These didn't smell bad, so they shouldn't be xanthodermus. Evidently they also weren't poisonous.

I don't know about the low phenol xantho idea, but I do know that some people have a natural tolerance to phenol, which explains the variability within that species. Some people can eat them, others can't. Either way, if strangebrew is right about the varying phenol levels, then fragrance alone is the only important feature for distinguishing poisonous from edible Agarics. If you're sure it's Agaricus, and it smells pleasant, it's good to eat.

[strangebrew]

I'm definitely no expert when it comes to Agaricus,

Yet you continue to pontificate in a long post about them.

Which makes me think they were A. arvensis?

Just plain wrong. Pink gills + intense yellow staining = xanthodermis.

Edited June 10, 2011 by strangebrew

[Undergrounder]

No need to be snippy about it, I'm just trying to contribute.

I can find plenty of credible sources that that describe young A. arvensis gills as pink. And I wouldn't call that staining 'intense', especially for a xantho.

[NSF]

No need to be snippy about it, I'm just trying to contribute.

I can find plenty of credible sources that that describe young A. arvensis gills as pink. And I wouldn't call that staining 'intense', especially for a xantho.

 

Undergrounder: I've had the same problem, wondering whether I'm throwing away delicious arvensis, just presuming they are xanthodermus. It doesn't seem to be easy to differentiate the two. Unfortunately, xanthodermus is so widespread and successful that whatever I find is more than likely xanthodermus. Even more likely it's A.x than campestris

I haven't yet had the pleasure of eating any arvensis though. I tend to only trust pink staining/bruising/discolouring when identifying campetris.

[strangebrew]

I ran across an old post of mine that I'd forgotten about where I mentioned seeing an expert on TV talking about xantho's. They said only 1 in 10 - 10% of the population, is going to have trouble eating them anyway. It seems as usual the powers that be are exaggerating the dangers. No one I know has suffered from eating them at all. The only reason they don't is that they can taste a little strong.

[Sola]

I'm pretty satisfied it's A. xanthodermis, with all the above details and the fact that it very quickly took over an entire outdoor mushroom patch.

There are literally dozens of them and more are appearing everyday but all the plants in the area are doing really well so I'm happy to let them go.

I'll start another patch elsewhere and try to get a tastier variety to colonise before they do.

And yeah I ate a whole pile of them in a pasta dish with no problems, didn't taste really strong of phenol but not the most tasty of shroms.

I think people beat up the potential risks because in some instances shrooms can be very difficult to identify and isolated cases with really poisonous shrooms can and have been deadly.

I certainly wouldn't touch difficult to identify Amanita's for instance and I know there are others but it's this one that for me and lots of others that springs to mind.