Observation 91598: Clitocybe sclerotoidea (Morse) H.E. Bigelow

collected by Peter Werner.

Species Lists


clitocybe sclerotoides.jpg
sectioned to show compressed, aborted Helvella tissue.
clitocybe sclero.jpg

Proposed Names

92% (2)
Recognized by sight: small, non-descript, parasitic clitocybes growing from aborted Helvella lacunosa.

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= Observer’s choice
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Sorry for perceived argument, Debbie.
By: Daniel B. Wheeler (Tuberale)
2012-04-08 14:04:39 CDT (-0400)

I’m trying to come to grips with what a sclerotia is. As a seeker of hypogeous fungi, I have found a few. But never really understood how they became what they were (with the exceptions of hypogeous Hypomyces lactifluorum and Hypomyces chrysospermum).

It seems to me that using the first definition (“comandeered fungal tissue serves as a sclerotium…”) got me thinking along lines of perhaps all Hypomyces grow from sclerotium under Dictionary of Fungi’s definition.

Another thread regarding sclerotia got me started on this train of thought. I know that Psilocybe and Morchella produce sclerotia, but had never thought of Clitocybe much in that regard. Then your observation hit me squarely, and seemingly obviously: another sclerotia! My experience with Helvella lacunosa throughout its life cycle while hunting for truffles gave me first-hand experience in seeing H. lacunosa in many different stages of C. sclerotoidea development. Sometimes the cocooning effect takes several days; sometimes less than a day! Typically the host becomes mummified over a series of several days, and eventually retreats to an underground form. Indeed many of my collections of the sclerotia of C. sclerotoidea were hypogeous to barely epigeous. This lead to the belief that the primordia were being engulfed before any epigeous development.

I also started finding mummified Rhizopogons and Truncocolumella, some of which had been totally consumed and were mere liquidy shells for Hypomyces chrysospermum fruiting, as confirmed by Dr. Trappe. The remains of these sclerotia had already deteriorated beyond the “firm, often rounded stage” and progressed fully into the “firmly integrated into the soil” stage. With Truncocolumella the gleba does something similar to Coprinus comatus, auto-digesting itself into a liquidy mass.

here is the official quote from the recently updated USDA Hypomyces monograph:
By: Debbie Viess (amanitarita)
2012-04-08 12:29:23 CDT (-0400)

“The Russulaceae J. P. Lotsy is the host family of preference for the agaricicolous Hypomyces species, with teleomorphs of eight species found only on species of Lactarius or Russula.”

I am well aware that common current belief is that Hypomyces lactifluorum, our western lobster mushroom, primarily parasitizes Russula brevipes.
That in no way negates my generalization that these particular parasites take on the form of the underlying fruit body, members of the Russulacea, including Lactarius and Russula.

The reason that this Clitocybe was named sclerotoidea is because it grows from a sclerotium, or rounded mass of hyphae composed of host tissue that does not contain spores. That ain’t no Helvella form that we see here! The official description of “sclerotium” in the Dictionary of Fungi allows for just these sorts of odd couples.

I am not sure why you continue to argue this point, but I’m done.

Lactarius? Russula, actually.
By: Daniel B. Wheeler (Tuberale)
2012-04-05 21:10:48 CDT (-0400)

“Frequently rounded” doesn’t mean always rounded, does it?

I’ve seen Helvella lacunosa fully developed where only a portion of the cap had white fuzzy mycelium. Colonizes the entire Helvella within hours, though.

Occasionally an upright mushroom will fall down when colonized: embarrassing at mushroom shows.

I find Cantharellus partially parasitized by … something. I’ve never actually seen it produce spores, so it may be an asexual stage of something else. Can the asexual stage of fungi form sclerotia?

Do all parasitizing fungi like Hypomyces form sclerotia first? Even when in an asexual stage?

not unless…
By: Debbie Viess (amanitarita)
2012-04-05 18:28:07 CDT (-0400)

your Hypomyces-covered Lactarius takes the form of a “firm, often rounded mass of hyphal tissue, lacking spores.”

Hypomyces covers the shape of an existing fruit body (Russula, Amanita, Boletus, etc.), which remains mushroom-like, even though the Russula never produces its own spores. The Hypomyces then produces spores upon the surface of the Lactarius under-structure.

Doesn’t fit the below definition in the least.

The aborted, rounded hyphal mass from which Clitocybe sclerotoidea grows does.

I recognize the definition.
By: Daniel B. Wheeler (Tuberale)
2012-04-05 17:49:55 CDT (-0400)

Using that definition, isn’t Hypomyces lactifluorum growing on Russula brevipes also sclerotia? In other words, how does a parasitized fungus differ from a sclerotia? Or maybe there isn’t one.

the definition that I gave below came directly from the Dictionary of Fungi.
By: Debbie Viess (amanitarita)
2012-04-05 13:58:12 CDT (-0400)

others may have different working definitions, depending upon the organism involved.

still, by official definition, this is indeed a sclerotium. Hence its latin name.

True that it acts like sclerotia.
By: Daniel B. Wheeler (Tuberale)
2012-04-04 13:26:19 CDT (-0400)

But is it really a sclerotia? Some of the material I’ve found this fungus growing from was barely differentiated from actual Helvella, which still had discernable stipe and cap.

My concept of sclerotia was that it was long-term storage food supply for fungal development later. Sometimes that later may be years in the future. But all C. sclerotoidea I’ve seen have been fruiting on the aborted, typically mis-shapen Helvella. If they were more than a few weeks old, I’d be very surprised.

comandeered fungal tissue serves as a sclerotium…
By: Debbie Viess (amanitarita)
2012-04-04 10:56:46 CDT (-0400)

The aborted Helvella functions just like other sclerotia…a mass of fungal tissue that serves as an energy reservoir (or as the Dictionary of Fungi calls it: “a firm, frequently rounded mass of hyphae with or without the addition of host tissue or soil, normally having no spores in or on it.”). But this sclerotium comes at no or little cost to the Clitocybe.

Sucks to be the Helvella, though! ;)


By: Daniel B. Wheeler (Tuberale)
2012-04-04 03:33:44 CDT (-0400)

sounds like sclerotia, no? I don’t know that this actually forms sclerotia, though. I’ve never found it wintering over, although it is extremely common in my area. Just sort of wondering if sclerotoidea means sclerotia-like or is more a reference to actual sclerotia?

Created: 2012-04-02 23:51:56 CDT (-0400)
Last modified: 2014-01-09 22:10:09 CST (-0500)
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