Yes, this is Octospora affinis. Please note that the name of the moss is Orthotrichum affine instead of Arthotrichum affine.

Bonjour,
Oui, Octospora affinis, espèce très commune sur Orthotrichum affine sur les branches de divers arbres, surtout aux endroits bien éclairés.
Il faut bien écarter les brins de mousse pour l'observer accrochée à la base des brins, souvent en colonies.
Amitiés
Gilbert

Dear Nick,
it is Octospora affinis, indeed.
See http://www.octospora.de/Oaffinis.htm for some details.
Probably, it was not recorded in England before.
Could you check for earlier records? I would be interested.

with best wishes
Jan

Salut Nicolas, Gilbert, Jan et tout,

Thanks for the confirmation and thanks Nicolas, for spotting my spelling mistake (I was thankfully able to amend this in my original post).

Gilbert, the habitat was exactly as you describe.

Jan - This species doesn't appear on our either of our national databases, so I presume that is hasn't been recorded in the UK previously.

Amitiés,

Nick

Hi all,
Octospora affinis is meanwhile the frequentest bryophilous fungus in our distrikt thanks to the knowledge of ecology and the enlarge of the host plant Orthotrichum affine.
Regards
Peter.

I suspect that this fungus - as with many other bryophilous species - is overlooked in the UK. Very few field mycologists study micro-fungi in general it is sad to relate, in contrast to many other countries in Europe. No fungi associated with Orthotrichum appear on the FRDBI, and yet O. affine is virtually ubiquitous:
https://data.nbn.org.uk/Taxa/NBNSYS0000022272

This is an area of study in which I must try harder myself . . . .
cordialement
Chris

Bonsoir,
Malgré sa grande fréquence, il est à noter que l'espèce se niche profondément entre les brins des touffes de mousse et n'est pas facilement visible sans une recherche appropriée.
Ca explique peut-être aussi qu'elle n'a été décrite qu'en 2006.
Gillbert

T'as raison Gilbert,
il faut toujours écouter les vieux!
Amitiés,
Marcel

Disons "les Anciens"
Amitiés
Gilbert

Je vois: T'es pas encore au lit...
Bonne nuit quand même,
Marcel

Bonjour à tous,

Chris a raison, the species has for sure been overlooked in UK. Since our '' young vétéran'' Gilbert found it 2 years ago and annouced its discovery, the species was searched and found nearly everywhere in France

 

Bonne année myco à tous,

Michel

Hello Nick et al.
It has not taken too long for a second UK record of Octospora affinis ;-)
I have not had any success before with small bryophilous ascomycetes, but encouraged by what I have read on this website, and by a recent e-correspondence with fellow ASCOFrance person Zuzana Egertová I have persevered. This collection was made on Orthotrichum affine growing on a well-lit mossy branch of Sambucus nigra about 75cm above ground; I don't know the exact locality for Nick's find but this latest locality must be at least 300 kilometres away (to the NW) and at a greater altitude (180 metres). So it is probably widespread in the country, but with very few people looking.

I'm sure I have got the identification correct?

Cordialement
Chris

Hello Chris, can you provide a locality?

The ID looks spot-on; I've put some DIC images of asci and ascospores from Nick's collection onto the FGB&I website, and the ornamentation is near-identical. Will start looking myself now....