Returning to the waterworks by the stream in Dene Park, I was able to confirm that one of the Alders is well attacked by the Alder Bracket, Mensularia radiata, as suspected earlier in the year when I had seen the old decaying brackets. Great to have a guess turn out OK!
Having found "Green Elf Club" staining on several fallen branches over the years I was very glad to finally find fruiting bodies on this particular one. Sadly these have dried out a little and the edges have started to turn in.
This could be Chlorociboria aeruginascens, the Green Elf Cup, or Chlorociboria aeruginosa, the Turquoise Elf Cup. The two species are indistinguishable except microscopically, eg on spore size. The apothecia, only a few mm across, usually have a very short stipe either centrally or laterally located, as seen here. C. aeruginascens tends to have a more lateral stipe than aeruginosa, but this is definitely not diagnostic.
The underside of the apothecia are slightly bluer-green and more felty than the upper side, as in the First Nature description. This also mentions the fruit bodies falling sideways as they age.
The previous records for Dene Park only name C. aeruginosa, surprisingly as it is supposedly the rarer. This sample and the others could be either or both of those species.
