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The Amateur Mycologist - Probably Metatrichia vesparium - But Unexpected Microscopic Observations Make Me Less Than 100%

The Amateur Mycologist - Probably Metatrichia vesparium - But Unexpected Microscopic Observations Make Me Less Than 100%

These posts are not for foraging. They are intended for entertainment and intellectual satisfaction only. These posts are not a field guide nor comprehensive in any way - their accuracy is not assured in any way. Do not eat wild mushrooms unless you are a professional, have substantial professional assistance or have a wealth of personal experience with a specific species. Do not make any foraging decisions based on these posts. To do so could be dangerous or life threatening.

This post does not include edibility or toxicity information

What is this bizarre panorama of chaos?

There's a lot going on in this photo and we're going to need to tease it all apart. But initially, we can summarize by saying it contains two different species of plasmodial/acellular slime molds, or Myxomycetes. There is the predominating red sporangia - or spore containing structures - on top of stalks and covered in a red fluff called capillitium, which is interspersed with spores.

Then on the bottom of the small ecosystem of wood are several yellow patches. These are a different species, but you can make out to the left of the photo some kind of sporangium structure, as well as bright yellow capillitium on the far right.

Let's label this same picture and take another look.

picture with labels.jpg

Hopefully that clarifies the various elements in the photo.

Today's post is going to be about the top, red, stalked organism, while next Tuesday's post will be an effort to decode the yellow one.

Now, let's try to get a look at the same scene without magnification in the wild.


The explosion of chaos in the magnified picture above occurs on a tiny scale.

These organisms - the final sporangia of these slime molds - are quite small and, sometimes, difficult to see when foraging. Other times, they amass in impressively sized colonies - either as the final spore bearing structures or as a pre-sporangia mass of slime - at which point they can be impossible to miss.

This was one of the former cases - and the only reason I found these tiny guys is because it was cold and snowy - and failing to find big, flashy mushrooms, I decided to zoom my focus in to a smaller scale. So if you ever take a walk in the forest and see someone meticulously analyzing every inch of a decomposing log, you may now have a sense of what they're searching for.

Let's start breaking this species down by characteristics.


This shot gives an even better notion of the scale involved.

These sporangia are not much more than one millimeter or so in their dimensions, at the largest. It should be noted here that there is actually a third organism likely involved in this piece of wood - and that is the white background. More than likely these sporangia are the result of a sporulation from some time ago. However the sporangia nonetheless survive structurally for awhile afterwards. The white floor they are growing from is the result of some kind of organism - I just don't know what.

It could be the desiccated remains of the Metatrichia plasmodium - although I don't believe that is white in color. Or it could be the sclerotium of a different slime mold - which is to say the long term hibernation mode some slime molds use to survive harsh environmental conditions.

Truthfully, I don't know what the white stuff is - and I wasn't able to discern much under the microscope. But luckily, these M.vesparium did not disappoint.


Here you can see the full sporangia structure, held aloft on a sometimes quite thick stalk.

These were not more than 2mm high at the maximum. These particular sporangia have not yet burst and released their fluffy red capillitium. Instead, the "goblets" which contain the spore mass here remain whole, and the apical - that is "relating to or denoting an apex" - cap is still firmly attached to the goblets.

The photos above depict what happens when the sporangia are ready to release their spores. The goblets break open by the coiled force of the capillitium, which springs out in a big scrunchy mass.

Remember, as we go through these photos that we are looking at the final stages in the life cycle of an organism that is profoundly different from a fungus. Even though these structures appear convincingly fungal in nature, the rest of the slime mold's life cycle is nothing like a fungus at all.

Let's get the spore mass onto a slide.


Using a razor blade I was able to extricate a hunk of the capillitium.

I cut this big piece a bit with the blade after this photo was taken in order to get a smaller piece to look at. I also sort of blotted the slide with the whole mass of capillitium in order to get it to drop a layer of spores. I placed one drop of distilled water on the spores and the mass of capillitium and placed two different glass slide caps on each sample, on the same slide.

Let's see what we get.


Ah huh...

I guess I should have suspected this kind of structure, given the springiness of the capillitium, but still seeing it magnified was a surprise.


tendril close up.jpg

How strange is that?

Here, at the microscopic level, things reach a new degree of confusion. This is a roughly 400x magnification of a single strand of capillitium. Although these strands form inside the same cavity in which the spores are produced, their production has nothing to do with the production of spores. The spores and the capillitium develop concurrently in the sporangia, but the capillitium is entirely sterile.

However, the capillitium do serve a spore related purpose, by all accounts. Their springy nature breaks open the sporangia to release the spores, and the dense, hairy texture can cause spores to stick to the capillitium for a time so as to better disperse from inside the sporangia.

Although I am fairly satisfied with this first microscopic slime mold observation - it also creates some problems. I believe the combined failure of proper sample preparation, with the lower quality of my camera and scope, makes capturing the fine details of the capillitium nigh on impossible.

For instance, these capillitium should be composed of 3 to 5 spiral bands - however that is simply not clear one way or another in this photo. The Handbook does specify that the individual coils of capillitium do bend 180 degrees about half way down their length - and we can see in this photo, as well as in the photo at 100x magnification. We can also see the spines running down its length. I tried to measure them, but I got mixed results that were not, I think, particularly edifying.

Unfortunately, the microscopic photos of the spores only added to the confusion.

spores with measured.png

These robust, ellipsoid looking spores further confuse matters.

Both of my sources describe the spores of this species as round, but here we clearly have a different shape. The length of the spores matches the range given in the Handbook for the diameter, wherein it is described as 9-11 microns. It also seems to me you can make out the "minutely warted" detail as well in this photo. The color, however, seems quite dark - although I did not prep this with KOH or a stain, and so they may be less translucent.

The question is, why is the shape so different? I don't know! There's so much I don't know about slime molds. This fruitful, tiny piece of rotting wood was only the second slime mold source I've ever found.

I was very tempted to make this into a full on species post for M.vesparium. This temptation was based on the obvious macro-characteristics of the sporangia and capillitium, which match the Audobon guide and online pictures precisely.

However, I have said many times before that if you are not 100% certain about the identity of a mushroom - or in this case a myxomycete - then you don't really know what that organism is - and to act like you do, however much you may want the organism to be what you think it ought to be - is foolish.

The fact is - although these specimens fit the macroscopic bill almost perfectly for M.vesparium, the spores establish a substantial distinction, and one which I can't simply ignore. But, whatever the heck this thing is, it is splendiferous and makes for some awesome macro photos. Next week we'll take a closer look at its bright yellow cousin.


Photos Are My Own

Microscopic photos were taken using an AMScope M150B entry level microscope. If you use microscopes, I'm quite sure you've never heard of this model - but its cheap and available on Amazon. The camera lens is also AMScope, MD35 - by far their crappiest microscope camera. But, still capable of material, relevant, and in some cases, dispositive, data collection. Lastly it should be noted that the precise magnifications are not easily deduced using the camera - but based on relative spore sizes compared to known microscopic photos from Kuo and other sources, I estimate 40, 100 and 400x.

Information Sources

[1][Gary Lincoff, Audobon Society North American Mushroom Field Guide, Cordyceps capitata, p.852]

[2][Myxomycetes A Handbook of Slime Molds - Steven Stephenson and Henty Stempen, p.137-138]

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