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Observation 10854: Agrocybe Fayod

When: 2008-09-10

Collection location: Hershey, Pennsylvania, USA [Click for map]

Who: James V. Gallagher IV (lbjvg)

No specimen available

Location: lawn
cap: moist, slimy, viscid, waxy; orange
Gills: adnexed vs free
veil – none detected
spore print: rust brown


9Spores scraped from spore print. There is the possibility of some contamination since the same paper was used for several prints. I used Grams iodine (the reagent used in Gram stains), moistened the razor blade with it to get the spores to stick to the blade and scraped directly from the spore p...

Proposed Names

-3% (2)
Used references: Audubon society field guide
-2% (2)
Recognized by sight: Adding an option for “I don’t know”
28% (1)
Recognized by sight

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= Observer’s choice
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Add Comment
Maybe Agrocybe putaminum
By: Douglas Smith (douglas)
2008-09-12 12:27:29 -05 (-0500)

There is an Agrocybe in the Flora Agaricina Neerelandica vol. 6 that is rust brown in age, and has spores that are 9.5-13.5 um in length, and this is Agrocybe putaminum. It should be 3-5 cm in diameter though, and this one look smaller. Also the germ pore should only be 1.5 um in size, and these look larger.

Anyway, that looks closest from all the Agrocybe I have… Might not even be Agrocybe… need more details to prove that one, but that looks to be the closest, unless someone else has an idea.

The iodine is ok, it doesn’t stain things that well, and since everything is yellow, unless you color correct the light, you don’t really get the yellow stain in the photo. With brown spored species, you don’t really need this, the spores are already colored, I usually take spore photos with KOH, which has no color, to get the color of the spore, you can use water also. To stain cell walls people usually use Congo Red, and the wash it out with KOH, so you get a clear background with the red cell walls, but like I said, with pigmented spores you don’t need that.

spore photos
By: James V. Gallagher IV (lbjvg)
2008-09-12 12:09:46 -05 (-0500)

The yellow is due to grams iodine that I used mainly as a counter stain so I could see the spores. Also as a possible replacement for Mezer’s reagent which also contains iodine.

Two spores are present in the photo – there is ample opportunity for contamination because I made several spore prints on one piece of paper and took no effort to prevent contamination. (I was not intending to take it this far.)

In the future I have resolved to make the spore prints directly on glass and make an effort to prevent contamination.

Should I continue with the grams iodine or is that too confounding?

Ah, look at that…
By: Douglas Smith (douglas)
2008-09-12 11:42:19 -05 (-0500)

Well, you’ve got spores! Not a bad photo either, although it is yellow. Did you use some sort of reagent that is yellow, or is that the light from the scope? The bulbs for scopes tends to be fairly yellow. If it is the light, you can look up the “white balance” features of the digital camera to calibrate for the light color.

In anycase, it looks like you have two spores there, or so. I think the larger smooth spores are from your mushroom. They are ellipsoid, smooth, and with a clear germ pore, also light colored. This knocks out Galerina which has roughened spores, without a clear germ pore (depending on the author and if Phaeogalera is a section of Galerina or another genus, doesn’t matter these aren’t Phaeogalera either). Smooth also knocks out Cortinarius or Gynopilus, germ pore knocks out Hebeloma (which I thought they might be), they are light brown so this knocks out Psathyrella or Panaeolus (didn’t quite think they were that…).

So, what does it give us, from the looks and the spores, really you’re left with Agrocybe and Pholiota, actually it could be either, but Pholiota tends to have yellow tones in the gills, and more viscid (but these are probably dried out), so my guess is Agrocybe. Although orange is a funny color for Agrocybes which usually don’t have much color.

To prove that now you need more micro-details, and that needs the mushroom, and a section of the cap surface, and the shape of cells on the gill edge.

Good spore shots,

don’t have the specimen any more
By: James V. Gallagher IV (lbjvg)
2008-09-11 21:31:09 -05 (-0500)

but I have the spore print. Maybe I can float some spores off that.

Ah, thats where I saw this name…
By: Douglas Smith (douglas)
2008-09-11 17:03:15 -05 (-0500)

Something was tickling the back of my mind on the G. venenata, this was one of the species, along with G. autumnalis and G. unicolor, that were syn. with G. marginata in a DNA study.

So, G. venenata, should just be thought of as another form of G. marginata, probably closer to G. unicolor, since that one is found more on the ground, and G. marginata and G. autumnalis are found on wood.

In any case, it doesn’t look like it, take a look at my photos of G. unicolor, since that should be the closest. And the field guide should have choosen the common G. unicolor to list, instead of the one time only G. venenata. Except there wasn’t the discussion about G. unicolor poisonings…

Just give it a try.
By: Douglas Smith (douglas)
2008-09-11 16:39:19 -05 (-0500)

For the spores at least, it is easy enough. You can get a spore drop on the slide, then just add a drop of water and cover-slip, and put it under the scope. For some genus there are questions about reactions with reagents, but you can ignore that at first.

If the mushroom is dried, or old, then just pluck out a gill with thin tweezers, place that on the slide with a drop of water and cover-slip. Tap lightly to work out any trapped air bubbles under the gill, and pop that in the scope.

For the brown spored stuff, the spores are easy enough to find, they will be brown, and other tissues usually aren’t. Also the spores will all be about the same size/shape and free floating. Stuff that isn’t similar will be contaminates.

You can check out Mushroom Expert site for notes on begining use of the scope. And once you get started then come back with more question on where to go next.

You can even get photos with the digital camera held up to the scope eye piece, and then post those so we can comment.

Oh, one thing, to really get details on spores you might try to get to 1000x, which will need immersion oil. If that isn’t easy enough, then just start at 400x without that and post the image for comment.

I’ll be waiting for an image of the spores on this one.

By: James V. Gallagher IV (lbjvg)
2008-09-11 15:17:09 -05 (-0500)

I actually have access to a nice clinical laboratory microscope (Olympus BX45). It is not optimized for mycology. Can anyone provide me with a reference on the technical details including specimen preparation, material needed (like glass slides, cover slips, special reagents), etc. I would like to give it a try if feasible.

No rhizomorphs
By: James V. Gallagher IV (lbjvg)
2008-09-11 15:07:01 -05 (-0500)

That must be grass strands included with the dirt.

It’d be a miracle
By: Douglas Smith (douglas)
2008-09-11 13:03:40 -05 (-0500)

There is very little chance this is G. venenata, it fact I have almost no idea why it was included in that field guide, since this species was id’ed only once and from the type location of Portland, OR. It is a little strange in that the species was sited as only a grass, where it is in the section Naucoriopsis which are usually on wood.

I think it was included because of the discussion about poisoning for this species in the monograph. Galerina are usually ignored for guides, except for the ones that have been accused of poisoning. Which gives a false impression that Galerinas are only wood growing deadly poisonous mushrooms.

On the other hand this little guy is kinda interesting as orange and brown-ish spored. And at that point, it general if you are looking at a little brown-ish, brown-ish spored guy, you need to get some microscopic details, or you won’t get anywhere. A photo of the spores at least here would help, otherwise, it is just all geussing.

By: J. Williams (jwilliams)
2008-09-11 00:36:45 -05 (-0500)

Are those rhizomorphs that are covered by dirt?