When: 2009-08-12

Collection location: Akademgorodok, Novosibirsk, Russia [Click for map]

Who: Tatiana Bulyonkova (ressaure)

No specimen available

Another puzzling little species (cap diameter < 3 cm) we’ve been unable to identify by photos. Unfortunately, no dried specimens (maggots win). Found in a small scattered group on soil and litter during a long, cool rainy spell last August under thick, Aegopodium-dominated undergrowth in mixed birch and aspen forest.

Macroscopically the cap has no striations and a minutely velvety feel. Flesh in both the cap and stem is thick and pure white with a strong, pleasant mealy odor. Note how the superficial concolorous pigmentation of stem surface ends abruptly near the top. Gills and spore print are also white.
This species appears to be rare here or have a sporadic fruiting pattern: the previous sighting was in 2006 in similar conditions.


Another specimen from late August, 2009
Here is a more robust specimen from 2006 showing extensive mycelial binding of the substrate
Finally a picture supported by dry material; these appeared in the middle of a bad drought and are a bit paler than those from previous years.
Grew on litter in Betula pendula + Populus tremula + Pinus sylvestris forest, with grassy vegetation dominated by Aegopodium podagraria and Pteridium aquili...

Proposed Names

-17% (5)
Recognized by sight: Trying to get some opinions on this one.
-6% (5)
Recognized by sight: I’m curious too..
59% (8)
Recognized by sight: my best guess

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

= Observer’s choice
= Current consensus


Add Comment
Just an update
By: Tatiana Bulyonkova (ressaure)
2011-11-01 01:11:51 CDT (-0400)

we’ve checked this little critter microscopically and it’s like nothing in the books, although C. obscurissima does seem to be the closest match. The pileipellis and spores are still a bit different (the pileipellis is pretty weird with a lot of strangely shaped, interwoven hyphae). I’m currently looking for iron acetocarmine to check the siderophilic reaction.
Irene, many thanks again for the hint to the right direction!

By: Irene Andersson (irenea)
2010-09-29 11:28:37 CDT (-0400)

for clamps, spore shape and possible structures on them, iodine reactions, or if they turn blue in cotton blue (cyanophilous), and see where that leads to start with..
I still can’t find anything like this in my books.

Specimen – at last
By: Tatiana Bulyonkova (ressaure)
2010-09-29 10:41:30 CDT (-0400)

…took me a lot of crawling around collecting spider web with my face, but at last I’ve found a specimen, namely, a group of three more or less mature fruitbodies growing in the same place where I found it in 2006.

The question is – what/how to look at microscopically? Any particular structures/reactions to look for? I’d really appreciate any advice!

Calocybe? Gymnopus?
By: Dimitar Bojantchev (dimitar)
2010-02-10 15:54:05 CST (-0500)

Looks to me like a Gymnopus or Calocybe. Thought of Melanoleuca a bit, but the gill attachment does not fit. Still, there are even more options in that group too… I can’t see Tricholoma in there. What was the spore color (in mass!)? A piece of dry material will demystify this one right away…

Irene, thanks! This narrows down the ID
By: Tatiana Bulyonkova (ressaure)
2010-02-10 11:02:25 CST (-0500)

Irene, wow, thanks for the version and link, they do look strikingly similar but for the shade of brown. According to IF the priority name is Calocybe obscurissima – so the current ID stays. The only Calocybe/Rugosomyces listed in the latest monograph on Western Siberian macromycetes (N. Perova, I. Gorbunova, 2001) are C. gambosa and C. ionides (even C. chrysenteron is not there although I find it every year) so there’s a big chance that this is a rare or even undescribed species.

I added two more images.

The colour
By: Irene Andersson (irenea)
2010-02-10 10:17:40 CST (-0500)

on gills, cap and stem doesn’t fit any Calocybe (Rugosomyces) in my books, but Rugosomyces obscurissimus (synonyms: Calocybe obscurissima, Tricholoma conicosporum) isn’t that far away after all.

Here’s one of the pictures I found:

It belongs to sect. Carneoviolacei (compared to sect. Rugosomyces with yellow gills, they have white gills, more irregular spore shape and different structure in the cap surface). Maybe this could be an undescribed species that belongs there? I hope you will find it again and let us know more.

I think it would be convenient if you add more pictures to this obs, but there could be other opinions.. Do what you think is best.

Agree, and still not a clue about genus
By: Tatiana Bulyonkova (ressaure)
2010-02-10 06:46:50 CST (-0500)

Irene, Noah, thank you,
you’re reading my thoughts.
Also, the flesh of this mushroom is just too brittle for Melanoleuca and Megacollybia, those are somewhat more pliant/fibrous (alas, no microscopic support for this tentative feature).
The closest I’ve seen in our forests is Calocybe chrysenteron, it has the same size, smell, flesh texture, and it also binds litter (coniferous, though) with cottony mycelium and fruits in similar small groups, but I couldn’t find anything even remotely matching this mushroom’s colour among Calocybe. I’ve found pictures from 2006 and another image of an unidentified mushroom which seems to be the same species – probably I should publish them as a separate observation or is adding them here ok?

Still curious
By: Irene Andersson (irenea)
2010-02-10 04:31:35 CST (-0500)

I agree with everything you said, Noah.
Other thoughts I’ve had are Melanoleuca, Megacollybia/Oudemansiella, Dermoloma, but I don’t really beleive in them either.

This one is weird
By: Noah Siegel (Noah)
2010-02-09 18:37:26 CST (-0500)

and it has been driving me crazy… It looks “sorta like” a lot of things but doesn’t look like anything (that I know)

My first thought was Tricholoma but I have never seen any with hairs on the base of the stipe like these, also the way it appears to be binding to the litter looks more like something I would expect from a saprophyte not a ECM…

Gill attachment
By: walt sturgeon (Mycowalt)
2010-02-09 17:55:54 CST (-0500)

Did not look like a Tricholoma but I agree otherwise.

Questionable – substrate doesn’t fit Tricholomopsis
By: Tatiana Bulyonkova (ressaure)
2010-02-09 04:04:09 CST (-0500)

Thanks, Walt!
The overall impression is indeed Tricholomopsis-like, but afaik Tricholomopsis are strictly wood decomposers, and these were fruiting on soil and rotting leaves, there were no twigs or buried wood – saprobic/mycorrhizal?

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