Observation 56575: Agrocybe erebia (Fr.) Kuhner ex Singer

When: 2010-10-20

Collection location: Rowan Co., North Carolina, USA [Click for map]

Who: Matt Sherman (Shermanii)

Specimen available

Rowan Co., NC

Found alone, growing from sandy soil on the bank of an old creek bed, in mixed, predominantly hardwood, forest.

2.5cm broad, convex, smooth, umbonate, viscid, creamy-brown with red-brown or dark-brown umbo, striate margin

Adnate to adnexed, creamy tan or creamy light brown, close to crowded

3.8cm long, .3-.4cm wide, ever so slightly enlarging at base, sort of shiny, creamy to creamy-brown, smooth, vertically filamentous, hollow, darker where handled (possibly due to moisture).
Partial veil beige to creamy-brown, superior annulus that flares upward.

Spore Print:
Chocolate to cinnamon-brown

Do not know what this is, any info would be helpful.

Species Lists


Copyright © 2010 St. Chibes
Copyright © 2010 St. Chibes
Copyright © 2010 St. Chibes
Copyright © 2010 St. Chibes
Copyright © 2010 St. Chibes
Copyright © 2010 St. Chibes
Cross section 200x in KOH
Lamellar hyphae 800x in KOH
Pleurocystidia and Cheilocystidia 200x in KOH
Cheilocystidia 800x in KOH
Cheilocystidia 800x in KOH
Pleurocystidia 800x in KOH
Cap cuticle in KOH
Hypodermium 800x in KOH
Hypodermium 800x in KOH
Spores 2000x in Melzer’s Reagent
Cap Cuticle 80x in Melzer’s Reagent
Cap Cuticle 200x in Melzer’s Reagent
Cap Cuticle 800x in Melzer’s Reagent
Cap Cuticle 800x in Melzer’s Reagent
Cap Cuticle 800x in Melzer’s Reagent. (I rolled the fine focus out and it revealed some spores and these long hair or filament-like structures. I don’t know if this has any significance or not.)

Proposed Names

-2% (2)
Recognized by sight
60% (4)
Eye3 Eyes3
Recognized by sight
Used references: Flora Agaricina Neerlandica vol. 6, p218.
Based on microscopic features: Viscid cap, cellular cap surface with narrow elements, lageniform pleuro- and cheilo-cystidia, ellipsoid smooth spores without a germ pore.

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Cap cuticle – Microscopy added
By: Matt Sherman (Shermanii)
2011-03-01 14:55:18 PST (-0800)

I added the cap cuticle and prepared the slide in the way you explained, Douglas.

I’m guessing I did this correctly…
Check it out if you’d like to.

Cap cuticle
By: Matt Sherman (Shermanii)
2011-03-01 12:23:02 PST (-0800)

Thanks for explaining Douglas.

To answer your question about the type of razor blade I’m using:
I’m using a single edge blade.
Should I be using a double edge?

I will post pictures of the cap cuticle as soon as I get it back under the scope.

I wouldn’t go so far there…
By: Douglas Smith (douglas)
2011-03-01 09:51:04 PST (-0800)

No, I don’t think that is a very good way to get a mount of the “cap cuticle”, to give you any taxonomic info. And it sounds like you are making your life harder in the process.

Take what you see there in the “cap cross-section”, that is what you are trying to see. At the upper right side there, that is the cap surface, or pileipellis, in cross section. That is what you want. If you had just gotten higher res on that upper right side edge, that gives you the detail that you need.

You should just take the dried material, still dried, and carefully shave off thin slivers in a “radial section”, inward from the cap margin toward the center. As thin as you get, and in a slight “wedge” shape, so one of the ends will be very thin as the razor leaves the cap. And you are using double-edge razor blades for this? Then with your micro-fine forceps (tweezers), pluck out the narrow sliver, and lay this down on the slide.

If it is thin enough it will lie down just fine, and one edge will be the cap surface in cross section. Then you can rehydrate this right on the slide with a drop of alcohol, and once that evaporates, then a drop of reagent.

I like to use 95% ethanol for the alcohol, since that evaporates quickly, and isn’t poisonous. But I think if you use any 95% alcohol it will be the same. I think the denatured stuff, you should check, it often has acetone and ketone in it, and I think that stuff might be harsh for the material, and desolve some features you might like to see. But I’m not sure if this is a real concern or not, I just got the 95% pure ethanol just in case.

For the cap surface, you don’t really want to use KOH. This can desolve the gelatin on the surface, it is is thin. Better to use Meltzer’s or distilled water there.

By: Matt Sherman (Shermanii)
2011-03-01 09:21:20 PST (-0800)

Thanks for looking into this Douglas!

So what I thought was the cap cuticle, is not?
How I’m preparing the mount for the cross section/cap cuticle:
I rehydrate a portion of the cap in 70% isopropyl alcohol for 1-2 minutes. Then transfer it into a dish of tap water for 1-2 minutes then remove it, roll it up, press lightly with a paper towel until it’s not so wet and start making thin cuts until I get the desirable thickness. Then I put the cut on the slide with a single drop of KOH or water and it starts to unfold. I help it along with a pin and put a cover-slip over it and there you have it.
(I learned this method from Michael Kuo’s website, www.mushroomexpert.com)

To view the cap cuticle (or what I thought was the cap cuticle), I just view the top part of the cross section.
Is this wrong?
Should I be making the cap cuticle mount separate from the cross section and using a different method to make this cut?

Thank you again for all of this information!

Thanks for the compliment bro!

good work Douglas
By: Jimmie Veitch (jimmiev)
2011-03-01 06:11:05 PST (-0800)

and microscopy, Matt

By: Douglas Smith (douglas)
2011-03-01 03:52:03 PST (-0800)

Ok, this one was annoying. There is that veil, but in the photos the cap surface looks moist. Looking at the cap section at 200x you can see the cap surface in cross section, and there is a layer of gelatin there, and the cap surface has these narrow up-right elements. So, it is either cellular or with a trichoderm. But if it is viscid, it should be Bolbitius with those dull brown spores, but that doesn’t have a veil. Pholiotina might make sense, but those don’t have gelatin on the cap. But some Agrocybe do have a gelatin layer on the cap. But Agrocybe should have spores with thicker walls and a clear large germ pore, unless, maybe some don’t. Like some Pholiotina don’t. Also there is the pleurocystidia, neither Pholiotina or Bolbitius have pleurocystidia. And those are such nice clear photos of pleurocystidia, there isn’t any confusion there.

So off to the books… and there it is. Agrocybe erebia, has a veil, gelatin layer on the cap, with narrow up-right cells, has pleuro- and cheilo-cystidia, and ellipsoid smooth spores without a germ pore. Turns out there are a few Agrocybe without germ pores.

The “cap cuticle” photo you have there, aren’t. Those are photos of the hypodermium, the layer of cells below the cap surface. With these guys, it is important to get a good section of the cap to look at the cap surface. Which you got earlier in the lower-res shot. Without that it would have been hard to get this. The gelatin on the cap surface was important.

Not sure how you are preparing the mount for the “cap cuticle”.

BTW – the notes in the description mention that the clamp connections are present, but rare or hard to see. Mostly present in the stipe surface.

Microscopy added…
By: Matt Sherman (Shermanii)
2011-02-28 21:41:24 PST (-0800)

Check it out if you like…

Created: 2010-10-25 10:31:13 PDT (-0700)
Last modified: 2015-04-04 20:28:07 PDT (-0700)
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