When: 2015-06-26

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

Who: Dave W (Dave W)

No specimen available

There appears to be a fungus parasitizing the gills of this Amanita velatipes.


Proposed Names

31% (2)
Recognized by sight
42% (3)
Recognized by sight: or the Amanita’s own hyphae growing out from the gills EDIT: remnants of the inflated cells which help separate the young gills from the stipe during FB development. thanks RET for the clarification.

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= Observer’s choice
= Current consensus


Add Comment
Thanks Rod.
By: Dave W (Dave W)
2015-06-30 11:49:21 CDT (-0400)

As always, very informative.

My guess is that it may have a temporary effect.
By: R. E. Tulloss (ret)
2015-06-30 08:54:12 CDT (-0400)

The amanita gill edge structures are designed to collapse and fall away. The structures are dominantly made of inflated cells that arise in chains. First of all, the chains break up to allow separation of gills and stem. Then those inflated cells that remain collapse, decay, and (often) fall away. You caught an interesting moment in your image.

For readers who are not familiar with Amanita: These structures are limited to amanitas. No other gilled mushroom originates in a solid mass and has to break apart in order to mature and drop spores.

A little about this unique development process (which is a defining character of the genus) can be found on the following page and on pages linked to it:


Very best,


Thanks Rod.
By: Dave W (Dave W)
2015-06-30 00:54:26 CDT (-0400)

Could this affect the ability of the mushroom to drop spores?

I don’t see hyphae crossing between gills.
By: R. E. Tulloss (ret)
2015-06-30 00:45:01 CDT (-0400)

There is not the sort of spreading of hyphae that I’ve seen in early development of, say, Hypomyces hyalinus attacking.

I noticed that there are no lines on the upper stem. Maybe what we’re seeing is a case in which all of the cells that allow separation of the gills and the stem ending up on the gill edges instead of leaving a significant amount of these cells on the stem (which is much more usual). Hence, the gill edges are far more decorated that usual.

Very best,


Something else about this A. velatipes.
By: Dave W (Dave W)
2015-06-29 22:36:08 CDT (-0400)

Despite its appearing to be in perfect condition to collect a nice thick spore drop, I had to wait for well over 24 hours for even a minimal print. Most of the area on the micro-slide surface placed under the gills showed only a wet residue. A few faint short lines of spore dust occupied a few square mm. I allowed the mushroom to sit out for another 24 hours, with little change noted in the amount of spore collected. So I think something had disrupted the normal spore-producing mechanism for this mushroom. The fuzzy structures on the gills seemed like a hypothetical candidate.