Postia species for ID

[RobSutton]

The snows gone, for a while at least, and I ventured out with the camera in the vain hope of something interesting and came across this little bracket growing on the dead trunk of an old birch tree.





I'm pretty sure it's a Postia species on the basis of the very small allantoid spores 4.3µ x 1.5µ with pronounced droplets at each end,



very conspicuous clamps



and the quite soft and easily squashed flesh. I thought at first it might be a non-blue Postia subcaesia but it dodn't look like any others I'd seen up here and there seemed to be some cystidia like cells in the hymenial layer that P.subcaesia isn't supposed to have:



Doing a bit of on-line reading (Basidiomycota Checklist) I came across a reference to a Postia leucomallella - a species that has been recorded on Birch according to the BioImages site. I don't have any books that mention this species at all. Does anyone know anything about it or have any online references I could look up? Alternatively, have I gone and made a basic error (as well as looking at bracket fungi in the first place as I'm sure Chris will remind me) and this is not a Postia at all?

As ever your help is much appreciated in advance - and a Happy New Year to you all.

[Ditiola]

Hi Rob

Using the simple key in Ellis & Ellis 'Fungi without gills' and from the information of Non Bluing and with cysdia and clamps it key out to P.leucomallela, but this is not a species I know.

Peter

[stickman]

Hi Rob

I'm pretty poor with these brackets, but have you ruled out Tyromyces?

If you have, I'd like to know how because I'm unsure which characters separate the two genera......

Cheers, Nick.

[RobSutton]

Originally Posted by Ditiola

Hi Rob

Using the simple key in Ellis & Ellis 'Fungi without gills' and from the information of Non Bluing and with cysdia and clamps it key out to P.leucomallela, but this is not a species I know.

Peter

Thanks Peter - I can't seem to find much about the species anywhere, my books are a bit limited with respect to the brackets.

Originally Posted by stickman

Hi Rob

I'm pretty poor with these brackets, but have you ruled out Tyromyces?

If you have, I'd like to know how because I'm unsure which characters separate the two genera......

Cheers, Nick.

The only Tyromyces in Fungi of Switzerland was a reddish resupinate T.placenta which clearly didn't fit. There were two others Leptoporus mollis and Loweomyces wynnei that had previously been classified as Tyromyces species that I eliminated on the basis of habitat or spore shape. So the simple answer is that I'm working from a rather limited set of reference material and matching up individual descriptions as best I can. There does seem to be a need for a Fungi Nordica that covers the bracket fungi (the old vol. three of the original series is unavailable and like the ascomycote volume doesn't crop up in the second hand market at all).

Any suggestions for other reference sources gratefully received.

[ashgale]

probably not the same thing at all, but there is something similar in this post,

fence post fungi

way out of my league this sort of thing, but some of the more knowledgeable users might know differently


ashgale.

[stickman]

Originally Posted by RobSutton

The only Tyromyces in Fungi of Switzerland was a reddish resupinate T.placenta which clearly didn't fit. There were two others Leptoporus mollis and Loweomyces wynnei that had previously been classified as Tyromyces species that I eliminated on the basis of habitat or spore shape.

Any suggestions for other reference sources gratefully received.

I am unfamiliar with the species you mention, although I am fairly familiar with Tyromyces chioneus, with which your microscopic description agrees with:

Tyromyces chioneus (MushroomExpert.Com)

It is quite common in my neck of the woods, and I think your substrate of birch fits well too, although I have not seen it in such a tiered growth pattern as in your photo...

The page I linked to above mentions 'cystidioles' which is a term I have not come across before - I would be interested in a definition if anyone has an idea??

Cheers, Nick.

[stickman]

Originally Posted by ashgale

probably not the same thing at all, but there is something similar in this post,

fence post fungi

way out of my league this sort of thing, but some of the more knowledgeable users might know differently


ashgale.

Hi ashgale

The fungus in the thread you linked is (the anamorph of) Postia ptychoaster

The teleomorph is seldom seen, although we can rule this out here as it usually grows from the centre of a mass of brown chlamydospores and is fairly thin and resupinate (rarely forming substantial shelves like in Rob's specimen). Also I would describe it's texture as papery-fragile-delicate, and it's spores are not allantoid if I remember correctly.

I will try to attatch a photo to the relevant thread

Cheers, Nick

[RobSutton]

Originally Posted by stickman

I am unfamiliar with the species you mention, although I am fairly familiar with Tyromyces chioneus, with which your microscopic description agrees with:

Tyromyces chioneus (MushroomExpert.Com)

It is quite common in my neck of the woods, and I think your substrate of birch fits well too, although I have not seen it in such a tiered growth pattern as in your photo...

The page I linked to above mentions 'cystidioles' which is a term I have not come across before - I would be interested in a definition if anyone has an idea??

Cheers, Nick.

Many thanks Nick it does seem to fit quite well - I did notice a sweetish smell in the fresh fruiting body which also fits in. I've just come across a description in MycoBank which also seems to help. I've not come across that site before and it seems really useful. Could still do with a good key to the Polypores though.

[diggleken]

Hi Rob, its quite common 'up north' round here certainly, Tyromyces chioneus and does layer and does have a quite tough body which can last through winter.
Cheers
Ken

[RobSutton]

Originally Posted by diggleken

Hi Rob, its quite common 'up north' round here certainly, Tyromyces chioneus and does layer and does have a quite tough body which can last through winter.
Cheers
Ken

Thanks Ken - what would I do without you all