16 Feb 2010, Ballachulish, Lochaber, NN08455756.  White fungus covering large areas of bark of Picea sitchensis in shady forestry plantation.  Large patches on several scattered trees, trees around them unaffected.  Affected trees often had rotten wood in the area of the fungus and holes that looked like they might have been dug out by insects or birds.  Fungus surface varies from thin layers of mycelium to a sub-odontoid or warted hymenophore.  Fungus is on bark, which becomes loose and falls off in places, mycelium is also on rear of bark and on exposed lignum.  Spores white, non-amyloid, 3.8-7 x 3.3-4.8 mu, broadly elliptical to subglobose, smooth and with a germ pore at one end.  Hyphae have obvious clamps.

Fungus outer surface on piece of bark.  Ruler divs 1 mm

 Graticule divs 2.5 mu in all pictures below.


Basidium to left, just above line