Observation 33746: Polyporus tuberaster (Jacq. ex Pers.) Fr.

When: 2009-07-14

Collection location: West of Bovec, East Julian Alps, Posočje, Slovenia [Click for map]

Who: amadej trnkoczy (amadej)

No specimen available

Some fresh shoots with buds and young leaves from otherwise rootless trunk of Alnus incana show that the trunk was still alive.

Lat.: 46.31986 Long.: 13.52137
Code: Bot_362/2009-1121

Habitat: Pebble island of river Soča, full sun, exposed to direct precipitations, average precipitations ~3.000 mm/year, average temperature 8-10 deg C, elevation 350 m (1.150 feet), alpine phytogeographical region.

Substratum: Alive trunk of Alnus incana sill in bark, downed and transported by high water and deposited on a pebble island of river Soča

Place: Soča river bed near Podklopca settlement, west of Bovec, East Julian Alps, Posočje, Slovenia EC

Nikon D70 / Nikkor Micro 105mm/f2.8

Species Lists


Motic B2-211A, magnification 1.000 x, oil, in water.
According to A.Bernicchia, Polyporaceae s.l., Edizioni Candusso (2005)
Some fresh shoots with buds and young leaves of Alnus incana from otherwise rootless trunk show that the trunk is still alive.

Proposed Names

47% (5)
Recognized by sight
Used references: A.Bernicchia, Polyporaceae s.l., Fungi Europaei 10, Edizioni Candusso (2005), p 486.
M.Bon, Pareys Buch der Pilze, Kosmos (2005), p 314.
R.M.Daehncke, 1200 Pilze in Farbfotos, AT Verlag (2009), p 1056.
Based on microscopic features: Spore dimensions: 12.8 (SD=1.0) x 4.6 (SD= 0.53) micr., Q= 2.8 (SD= 0.19), n=33.
61% (2)
Based on microscopic features: spore size fits.

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
shape of pores and overall size
By: amadej trnkoczy (amadej)
2010-02-19 11:30:27 CET (+0100)

Dan thanks again. Although spore dimensions and shape of pores fit well to P. tuberaster I don’t believe this is a good option. P. tuberaster should grow from an underground sclerotium or from well rotten wood laying on or underground. ‘My’ log was hard, almost ‘healthy’ wood laying on clean white river pebbles and sand, no humus.

Pore shape of the specimen photographed is a problem indeed. Regarding pore shape Bernicchia (2005) states only ‘…angular, 1-2 mm…’. He doesn’t mention elongated shape. However, there are some sites on net which show somewhat oblong pores for P. squamosus (admittedly not as much as in my observation). For example:

- http://www.mushroom-collecting.com/mushroomdryad.html
- http://botany.upol.cz/... squamosus&czech=Choroš šupinatý&descr=rourkovitý hymenofor
http://botany.upol.cz/... squamosus&czech=Choroš šupinatý&descr=rourkovitý hymenofor

- http://www-lib.iupui.edu/...
- http://www.fungiphoto.com/CTLG/IMAGES/IM/0512-30.JPG . But it is an open question how much all these determinations are correct.

Overall size (‘meatyness’) of my fund is very small compared to average data from literature for P. squamosus. Some state pileus diameter up to 60 cm. But Mushroom Expert states pileus from 5-30 cm (and thick contex!). So, my observation falls somewhere around the minimum, at least according to his reference. This may eventually be explained by unusual habitat story?

Anyway, the mushroom seems to me very beautiful even if it name remains unclear.

pore size
By: Dan Molter (shroomydan)
2010-02-18 23:17:48 CET (+0100)

This specimen does look a little meaty for P. alveolaris, but doesn’t look meaty enough to be P. squamosus. The wide “hexagonal” pores also point away from P. squamosus. I don’t know about the spore size. Interesting find!

Explanation appreciated!
By: amadej trnkoczy (amadej)
2010-02-18 21:53:56 CET (+0100)

Thank you for your suggestion Dan. Please, be so kind and explain on what characters you base your proposal. Initially I considered P. alveolaris too, but didn’t decide for it mainly because spore dimensions fit much better to my first guess. Also for P. alveolaris contex in pileus (1-2 mm, Bernicchia (2005), p456) is much thinner than pore layer (5 mm, ibid.) while the opposite is true for P. squamosus. Picture 78494 shows and extremely thin pore layer compared to contex. Further, it seems that P. alveolaris lives on dead wood only, while P. sqamosus can live on both live and dead (ibid.). The Alnus trunk on which I found the mushroom was still alive with fresh new sprouts and leaves. Probably the trunk was downed not far back by high water. Wood was hardly at all rotten. Damages of the bark and wood you see on my pictures are mainly due to transport of the trunk by high water.

Another issue is that P.alveolaris is not listed in our Slovenian fungi check list (2.800 species for 20.000km2 area). Also Bernicchia (ibid.) states that in neighboring Italy it is not really a frequent fund. Did I photograph something not yet found and described in Slovenia? I doubt. So, a kind of mess in my head! Therefore I would like to know reasons for your decision. Thanks in ahead.

Created: 2010-02-18 17:18:40 CET (+0100)
Last modified: 2018-07-16 17:43:42 CEST (+0200)
Viewed: 176 times, last viewed: 2018-07-23 21:54:25 CEST (+0200)
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