Verdigris Puzzle

[Fungus Ken]

FungiJohn's image below shows one of the species of what was known as Verdigris Agaric. However, there are actually two closely related species, Stropharia aeruginosa and Stropharia caerulea (now known as Blue Roundhead). They are not always easy to separate.



Volume 4 of Flora Agaricina Neerlandica says:

"Psilocybe caerulea can easily be distinguished from Ps. aeruginosa by its often incomplete annulus, paler lamellae with concolorous lamella edge ..."

Let's leave aside the decision to move these species to Psilocybe because this is not yet accepted in Britain. It's not actually that simple to separate the two species, but you can see in the photo above that the ring
is not very well developed.

Compare with the images below, which I would say are of Stropharia aeruginosa and then see what you think about the species in the picture above.





(Thanks to FungiJohn and LaurieK for the helpful and clear images.)

Food for thought?

Ken

[Leif]

Apparently S. aeruginosa has a purple brown spore print, whereas S. caerulea has a pinkish brown spore print. That is according to Phillips.

[cybershot]

One of the biggest stumbling blocks in comparisons of such images is the different stages in development.

[Fungus Ken]

Yes, the different stages of development and the fact that age and weather conditions can remove useful characters is a problem (or a challenge?).

But the volumes in Flora Agaricina Neerlandica are written by the leading experts on particular groups of fungi, so if they suggest that the nature of the ring is an important feature in separating the two species in the field, it would be sensible to give this some weight. And it is certainly worth keeping in mind the options when you find one of the species in this group (there is also Stropharia pseudocyanea) to see if the characters suggest one particular species or another. Otherwise you end up lumping them all into one collective species.

In as far as you can take things with photos, I would suggest that the top photo is probably Stropharia caerulea.

Ken

[lauriek]

If the colour is true on the first shot, (which I would guess it is from the background, which doesn't look discoloured) then that is much bluer than the specimens I found, which were much more greeny blue and are aging into a manky greeny yellowy colour now... I'll take another shot of them tomorrow if they're still there and upload to this thread!!

[arvensis]

Isn't there a third species - S. pseudocyanea? Courtecuisse and Duhem describes the differences between the 3.

Mark

[FungiJohn]

Certainly food for thought there Ken. I'll run it past Ken Rowland for his comments.

Many thanks - John

[arvensis]

Just looked on the UK database and S. pseudocyanea is recognised as a species so that's 3 very similar species.

Mark

[Fungus Ken]

Originally Posted by Fungus Ken

And it is certainly worth keeping in mind the options when you find one of the species in this group (there is also Stropharia pseudocyanea) to see if the characters suggest one particular species or another. Otherwise you end up lumping them all into one collective species.

Ken

Yes, as I said above, Stropharia pseudocyanea is one in this group but it is relatively easily distinguished by its usually smaller cap size, a cap colour that is not as intense as the other two species but tends to be more of a faded ochraceous colour with hints of turquoise, and a distinctive smell.

Ken

[arvensis]

Well that serves me right for not looking closely enough at you posts! Luckily enough Courtecuisse and Duhem does cover all 3 species. It maybe just me but the blue strophs are quite photogenic species.

Mark

[Fungus Ken]

I guess that's one of the features that got me interested in fungi in the first place - the astonishing colours and beauty of some species, along with the fascinating smells and tastes.

Ken

[FungiJohn]

Originally Posted by Fungus Ken

I guess that's one of the features that got me interested in fungi in the first place - the astonishing colours and beauty of some species, along with the fascinating smells and tastes.

Ken

and here's another from Longshaw Ken The colour btw is correct too! I dare not name it

[FungiJohn]

What would you say Ken
John

[Fungus Ken]

I'd chicken out and say that it's easy to tell the species apart microscopically. Stropharia caerulea has lots of chrysocystidia along the gill edge. When stained with KOH these are easily visible and unmistakeable with their contents stained yellow by the alkali.

Stropharia aeruginosa and Stropharia pseudocyanea have no (or very few) chrysocystidia. To separate these two species, Stropharia aeruginosa has a distinct ring on the stem, while Stropharia pseudocyanea has a poorly developed ring. But the spores of the latter species are also somewhat larger on average.

In the field I do try to have a guess at which species I have found, and my hunches often prove right. But from a photo ... that's asking for trouble! As soon as I suggest a name, you'll no doubt go and prove me wrong by looking for the chrysocystidia.

Ken

[FungiJohn]

Originally Posted by Fungus Ken

I'd chicken out and say that it's easy to tell the species apart microscopically. Stropharia caerulea has lots of chrysocystidia along the gill edge. When stained with KOH these are easily visible and unmistakeable with their contents stained yellow by the alkali.

Stropharia aeruginosa and Stropharia pseudocyanea have no (or very few) chrysocystidia. To separate these two species, Stropharia aeruginosa has a distinct ring on the stem, while Stropharia pseudocyanea has a poorly developed ring. But the spores of the latter species are also somewhat larger on average.

In the field I do try to have a guess at which species I have found, and my hunches often prove right. But from a photo ... that's asking for trouble! As soon as I suggest a name, you'll no doubt go and prove me wrong by looking for the chrysocystidia.

Ken

Thanks Ken. I'm preparing a slide right now

In the field I was tempted with pseudocyanea as the ring was noticeably absent

John

[Fungus Ken]

OK. Let me stake my claim. If I was looking at this in the field (where I'd have a bit more info on the jizz) I'd say this was Stropharia caerulea. It doesn't look to have the washed out yellowish appearance of Stropharia pseudocyanea and it doesn't have a very distinctive ring.

The cards are in your court ... or should that be the balls are in your hand?

Ken

[FungiJohn]

I was hoping you would come back Ken I'll let you know what I find
John

[FungiJohn]

Chrysocystidia stained a definite yellow Ken. Shall we say Stropharia caerulea … Oh, you did

Many thanks again.

John

[Fungus Ken]

The three species do have their individual jizz but I have to keep bringing them back to check microscopically just to be sure I am still on the right lines.

Ken

[FungiJohn]

I've still to check under the microscope, just to prove one or the other ... possibly!