Observation 23208: Paxillus filamentosus Fr

When: 2009-07-13

Collection location: Geneva, Switzerland [Click for map]

Who: Douglas Smith (douglas)

No specimen available

Found and id’ed by others at the SMG meeting. I among other called these P. involutus. But others pointed to notes in books about another species P. tomentosus because of the quality of the cap surface here.

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P. involutus with Alnus sp.
By: Anna Gerenday (AGerenday)
2010-10-31 20:31:39 CET (+0100)

I would like to pick up on this topic. I just now searched for P. involutus and I am intrigued by some of the comments. I am in the US, Minnesota where only 2 species of Paxillus are known: P. involutus and P. vernalis. I am collecting in a small bog with Alder and Birch as woody plants, and I am finding a Paxillus species always in the viscinity of Alder. Based on spore measurements I decided that it was P. involutus (habitat would rule out P. vernalis); it also ruled out P. filamentosus. My previous experiment tells me that P. involutus occurs with conifers that are not present here because the bog is surrounded by an oak forest.
My questions: how was it established that P. involutus does not form mycorrhizae with Alnus? does it form mycorrhizae with birch? Could you suggest a good reference on Paxillus taxonomy and its mycorrizae forming ability?

By: Erin Page Blanchard (CureCat)
2009-07-16 13:48:22 CEST (+0200)

That is good to know!
I was aware that P. rubicundulus used to be P. filamentosus, however I was unsure whether P. rubicundulus was split off as a separate taxon, or if the name just changed.
Thank you for clearing that up.

All I want to add is just
By: Gerhard Koller (Gerhard)
2009-07-16 13:32:13 CEST (+0200)

that Paxillus filamentosus and Paxillus rubicundulus are the same but that there are two other species in Europe, namely Paxillus validus which is supposed to grow under hazel, and Paxillus obscurosporus with darker spore print but those two species seem to be doubtful though. And I have never found Paxillus involutus with alders altho sometimes alders can be mixed into the habitat where it grows but are not involved in mycorrhiza with it.

By: Erin Page Blanchard (CureCat)
2009-07-16 12:18:51 CEST (+0200)

’Aight cool. All that busyness sounds fun.

We all inadvertently make up names some times! No worries. :)

Ooops – sorry -
By: Douglas Smith (douglas)
2009-07-16 11:31:21 CEST (+0200)

Ok, sorry, somehow between the meeting, books, discussion, photos, notes, posting I just made up the name P. tomentosus (actually I think I made up the name P. tomentosa…). I really meant P. filamentosus. Good others pay attention here…

Alnus associated Paxillus
By: Erin Page Blanchard (CureCat)
2009-07-16 04:53:58 CEST (+0200)

Well first, I have never heard of P. tomentosus… Though there are a lot of similar names, such as P. filamentosus, as suggested, along with P. atrotomentosus which is actually a Tapinella, so T. atrotomentosa is the preferred name, but anyway.. There is also P. brunneotomentosus, and P. griseotomentosus, but I’m not familiar with those species.

Returning to P. filamentosus; there is one other European Paxillus associated with Alnus- P. rubicundulus, which can also have a cracked or broken up pileus. The only Alnus species that I am sure P. rubicundulus associates with is A. glutinosa.
P. filamentosus also associates with A. glutinosa, as well as A. tenuifolia. There is one study that suggests association with A. incana, A. sinuata, and A. rugosa. A. serrulata seems to be a fairly well established symbiont with P. filamentosus, though there is one study that says that this Paxillus species does NOT associate with A. serrulata… Though I’m pretty skeptical considering that they also assert that P. involutus DOES associate with this Alnus species. Sounds like someone screwed up if you ask me.

So Anyway, I doubt that anyone noticed the Alder species that this was growing with… and even then, I wouldn’t know the first thing of trying to distinguish P. filamentosus from P. rubicundulus, so I am not sure why I just typed all of that. :)

Oh yeah, get a collection next time you find a Paxillus other than P. involutus. I think Else is interested.

P.filamentosus differs from P.involutus
By: Gerhard Koller (Gerhard)
2009-07-15 22:19:49 CEST (+0200)

in habitat (it grows under alders) and in the color striations on the cap and is by far more seldom than P.involutus which is a mass mushroom in some years altho he is becoming rarer in the last ten years or so …

Created: 2009-07-15 17:34:33 CEST (+0200)
Last modified: 2009-07-15 17:34:33 CEST (+0200)
Viewed: 424 times, last viewed: 2018-09-30 09:02:56 CEST (+0200)
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