Parmelia saxatilis with apothecia

[Steve]

Hi,
We spotted apothecia on a Parmelia-type licen on acid gritstone, Peak District. I don’t think I’ve ever seen apothecia on Parmelia in the Peak District.
The reddish-green colour of the apothecia puzzled me as I know Parmelia usually have red-brown apothecia. However, it had been wet and I wonder if the algae were dominating the fungal colour.
Looking at Dobson’s (2005) key:
Thallus grey-green when dry. Upper surface K+ yellow (when absorbed onto tissue).
With isidia (yes).
White pseudocyphellae as white lines and dots. Coralloid isidia. No marginal cilia (yes).
This gives Parmelia saxatilis ( P. ernstiae excluded as it has a pruinose upper surface).
Simple or rarely squarrose rhizines (these look more furcate).
Apothecia lecanorine dark red-brown (these are reddish green) margins thin and frequently isidiate or crenulate (yes).
Spores simple 16-18 x 9-11 (these are a little smaller). (No reaction with KOH and then Lugol, but I only added Lugol once - not 3 times as in Dobson ).
Paraphyses look as in Dobson's diagram.
Medulla K+ red/orange (yes).
I presume this is fertile Parmelia saxatilis.
Steve

[diggleken]

Hi Steve,
yes it is classic Parmelia saxatilis - I have a place here near me in Saddleworth where it fruits , seemingly , all the time -and apothecia are your colour and darken with age -they persist well. Not often found like this, but seem to fruit abundantly when in the right conditions .
Jennny S site shows your apothecia colour well:
http://www.irishlichens.ie/pages-lichen/l-03.html
And you may have missed you also have remnants of probably Marchandiomyces corallinus in your pics!
Nice to see Lichens being dealt with so comprehensively, nice one.
Cheers
Ken

[Steve]

Hi Ken,
Nope! I spotted the little parasite in the piccie - it's abundant in parts of Longshaw.
One I haven't found on Physcia at Longshaw is Illiosporiopsis christiansenii - I searched all year. I found it the first time I looked at Idle Valley in Nottinghamshire. It's been found by Alan Smith in north Sheffield, so it's around.
Steve

[diggleken]

Sorry Steve, should have known..........
That is a cracking shot of Marchandiomyces!
Illosporiopsis christiansenii was always thought to be rare, but when you start to inspect Physcia you see it a lot, certainly round here - and I sent some records over to Chris Yeates as we were seeing them virtually every time we looked.
It must be just under-recorded as there aren't that many Lichenologists around - and many fungi folk wont be looking for it really. They may now a bit more as its more openly known to be more frequent these days after social media/WAB etc had some content about it.
Cheers and happy new year!
Ken