Observation 116229: Mycena (Pers.) Roussel

When: 2012-11-06

Collection location: Davis, California, USA [Click for map]

Who: Byrain

Specimen available

Growing in grass near the sidewalk border, they were tiny and had a rooting stem.

Spores non-amyloid.
Spore range = (8) 9 – 10 × 5 μ
Average spore = 9.45 × 5 μ
Q range = 1.8 – 2
Average Q = 1.89
20 spores mesured.
2-spored basidia observed.
Cheilocystidia measurements = 33×10, 34×11, 36×10, 40×13 μ
Pleurocystidia & caulocystidia not observed.

I tried keying this out in North American Species of Mycena and got lost in subgenus Eumycena section Deminutivae, then trying A Key to Norwegian Mycenas i ended up at M. flavoalba which doesn’t seem quite right, but at least similar. The key at mushroom expert leads me to M. flavoalba as well…


Spores, 1000x, mounted in melzers
Spores, 1000x, mounted in melzers, 1μ divisions
Pileipellis, 400x, mounted in melzers, 2.44μ divisions
100x, mounted in melzers

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Byrain
2012-11-29 02:46:00 PST (-0800)

I was able to make a good scalp section of the upper stem when I scoped this initially, I saw no caulocystidia or anything interesting, just hyaline smooth hyphae. If you look at the 3rd macro picture of the gill close up, you can see the upper stem appears mostly glabrous which may support this? Pleurocystidia also appeared absent. The 2 spored basidia, large spores, and lack of pink colors especially on the younger specimen concern me, I’m not sure M. floridula is a good name either. Also, in my limited experience with Psathyrella and Bolbitiaceae, I would think the cheilocystidia apex would carry some significance, but I don’t really know if this carries over to Mycena. :)

And thanks for the suggestions, I’ll definitely try your staining method. I told myself the other day that I will make an effort to get some congo red early next month. Though I don’t like pressing down the cover slip with an eraser, I find something with a needle fine point works much better. I personally use a dissecting needle with a bent end which also works well for crush mounts and getting tiny sections onto the slide.

Edit: I also understand that identifying lbms from photos can be difficult, but I appreciate your efforts nonetheless!

Mycena microscopy
By: Sava Krstic (sava)
2012-11-28 22:50:08 PST (-0800)

A Mycena is often difficult to identify from photos alone. I’ve been working on them for a year now and it’s been fun, but frustrating too. For other MO enthusiasts interested in this genus, there is a good short article “Making a start on Mycena” by Richard Iliffe available on the web. It helped me.

Below is a quote from Iliffe’s paper about examining cheilocystidia. I follow this procedure, with one addtitonal step: I wick off most of the Congo Red after the gill piece has spent a minute in it; then I add a drop of KOH and put a cover slip on. This improves visibility and produces less air bubbles.

Cystidia: We are primarily interested in cystidia on the gill margin (cheilocystidia). A very few
species have cystidia on the gill face (pleurocystidia) but we usually only need to know if these
are present for unfamiliar or rare species. To examine for marginal cystidia place one gill on a slide
and cut off a tiny sliver from the margin. The smaller the piece the better, and it is best to do this
under a low power microscope. The size of the piece of tissue should be no more than about half a
millimeter deep and 2 —3 mm long. Ideally it should be so small that you can hardly see it! Place
a drop of congo red or other stain beside the sample so that it spreads and envelops it, taking care
to keep an eye on the orientation of your section as if it floats and rotates you need to know which
edge is the marginal one. Lower a cover slip carefully so that it drops in the direction away from the
margin you wish to examine to encourage air bubbles to move away. Tap the cover slip several
times with an eraser on the end of a pencil to spread the tissue, or alternatively press down with the
eraser and give a quarter turn — this tends to break up the tissue better and to separate out a few
cystidia from the gill margin so that you can see their full extent. Even if your section is too large
and refuses to squash you will often be able to see whether the cystidia are spiky, or rounded with
granules on them, which in many cases is all you need to know. A selection of the various forms of
cheilocystidia is given on the following pages.

By: Sava Krstic (sava)
2012-11-28 22:35:57 PST (-0800)

Apologies for failing to notice your picture of cheilocystidia last night. Indeed, their tops are not as slim as in drawings for M. flavoalba. But who knows how much variation there is actually?

At this point it would help to have information on caulocystidia (near stipe apex). Robich also has drawings of the hyphae of the pileipellis that show curious spheroidal cells (3-15 microns), which would be good to confirm. It may be hard though, because of the dense gelatinous matter that obscures the features.

About the rooting, Robich explicitly says “base not radicante”. And I suppose he says it because for the stem of the closely related (if not the same) M. floridula he notes “base che si presenta con una radice di circa 20 mm”. Aronsen’s discussion (http://home.online.no/~araronse/Mycenakey/floridula.htm) is interesting too.

By: Byrain
2012-11-28 09:00:00 PST (-0800)

The 3rd micro shot shows the cheilocystidia, the pictures are not great, but you can still see the shape including the base on some of them. They are comparable to the M. flavoalba cheilocystidia illustrated here http://www.mycena.no/Bilder/flavoalba.gif , but with a shorter neck and more rounded apex.

I try to harvest all tiny and delicate mushrooms by digging a pocket knife under them and slowly lifting them out. The rooting stems slid out of the ground during this process and I’m not sure what the bases were connected to, but the habitat was just a short strip of lawn turf next to a pedestrian sidewalk.

For the section, I’ve been trying to follow what is written in How To Identify Mushrooms to Genus III: Microscopic Features, but still need much more practice. If you have any additional suggestions, I’d love to hear them :)

By: Sava Krstic (sava)
2012-11-27 22:32:29 PST (-0800)

How did you get the roots out; was it growing in humus?

Nice observation, but to move on with the ID, we’d really need to see the cheilocystidia. I’d be happy to provide instructions for slide preparation if needed.

Created: 2012-11-09 11:04:06 PST (-0800)
Last modified: 2013-03-12 23:46:27 PDT (-0700)
Viewed: 108 times, last viewed: 2017-06-14 07:20:15 PDT (-0700)
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