“When Mollisia does get finally properly revised at the species level (i.e. when some money becomes available to do the work), I think it should require a big collaborative group effort involving lot of redescriptions, recollections and sequencing, otherwise it'll become a horrible mess - so keep hold of your specimen and images until then!”
This is the sensible advice I got from Brian Douglas at Asco France.
The comprehensive online key at
http://www.mollisia.de/Schluessel_englisch.html
is anonymous, but seems to be authoritative. It lets you know that you really need to look at fresh material, and that each determination is going to be a big job, involving chemistry. There seems to be increasing evidence appearing that looking at dead herbarium specimens is not equivalent to looking at fresh material, meaning that you can’t necessarily just dry everything down and do ID's later if you ever find the inclination or time.
The alternative is perhaps (a) stick to simpler ID resources eg Ellis and Ellis, Peter Thompson, and put a name to your Grey Disco – knowing that it is not really adequate in light of current research, (b) limit yourself to just one Grey Disco per survey and submit your detailed findings to peer review e.g. Asco France or (c) bite the bullet and simply record them as Grey Discos, with a brief description of substrate and some basic microscopy e.g. spores etc. I've done this on the attachments.
As we’re surveying Longshaw with the (optimistic) aim of describing overall fungal abundance, as well as diversity, we might have to use option (c) more frequently. We collected 5 specimens last Wednesday 20/5/15 – four of which I looked at as carefully as time would permit, one which I discarded as I had had enough!

Steve