Another entry in the occasional series of updates on the species recorded at Taf Fechan and this is a fascinating one.
Exidiopsis effusa is one of the hundreds, if not thousands, of normally invisible fungal species living inside dead wood happily and quietly digesting away; however its particular presence is revealed rather spectacularly by the formation of Hair-ice.
Hair-ice is generally found on fallen branches that have bark missing exposing bare wood, it forms when the air temperature is just below freezing but the ground remains just above and it always forms only when this fungus is present.
All living, metabolising fungi produce carbon dioxide, this acts to push water out of wood which would then normally just freeze as a simple crust of ice, but E. effusa causes this water to freeze into thin hair-like strands.
It is thought that it produces some kind of "re-crystallisation inhibitor" which somehow acts to create and stabilise the delicate hair-ice whilst also acting to prolong its life.
I found these examples nearly a year ago but the link with E. effusa has only recently been discovered and was brought to my attention by the Glamorgan Fungus Group who have an excellent, friendly and most informative Facebook group by the way, why not join today? (Plug, plug)