There is a Paxillus that I can't identify that grows every year
in my garden. It is very like P. involutus, but is twice the size
(8-12" in diameter). It is either mycorrhizal or harmlessly
parasitic on birch.

Any ideas?


Regards,
Nick Maclaren.

In article ,
(Nick Maclaren) writes:
|
| There is a Paxillus that I can't identify that grows every year
| in my garden. It is very like P. involutus, but is twice the size
| (8-12" in diameter). It is either mycorrhizal or harmlessly
| parasitic on birch.

Hmm. Well, I looked at a copy of Carleton Rea in the UL, and am no
wiser. P. involutus is still by far the closest match, but it is
supposed to be MUCH smaller (2.5x in diameter). P. atrotomentosus
doesn't match at all well, and P. giganteus is even worse.

One other possibility is that it was brought in on the birch tree,
which may have been imported, and is not one of the 15 species
described in Rea as native to the UK. Well, if so, it grows here
now :-)


Regards,
Nick Maclaren.

A last followup.

http://www.bioimages.org.uk/HTML/B147197.HTM

Hah!

If all of the books have been wrong about the size of P. involutus,
as Alick is quoted as saying, then that is the likely species. I shall
fiddle with ammonia, and see if I can manage to make my father's field
microscope work on the spores, but it was really only the size that
made me doubt P. involutus.


Regards,
Nick Maclaren.

Nick Maclaren wrote:
There is a Paxillus that I can't identify that grows every year
in my garden. It is very like P. involutus, but is twice the size
(8-12" in diameter). It is either mycorrhizal or harmlessly
parasitic on birch.

Any ideas?


Regards,
Nick Maclaren.
P. involutus is a very common mycorrhizal fungi associated with various
birch species locally. It often reaches 6-8 inches, and I wouldn't be
surprised to see a 12" diameter specimen, although IMO few are likely
to reach that size.

Daniel B. Wheeler

In article ,
" writes:
|
| P. involutus is a very common mycorrhizal fungi associated with various
| birch species locally. It often reaches 6-8 inches, and I wouldn't be
| surprised to see a 12" diameter specimen, although IMO few are likely
| to reach that size.

From the reference in Field Mycology, it appears that few books have
caught up with even the 6-8". With the correction that up to 10" or so
occurs, everything falls into place.


Regards,
Nick Maclaren.