I will sugest O.quaestiformis, but the conidia are not belong to this spec. OR are immature (?).
We should wait for Zotto's comment.

Il semble qu'il n'y a pas de crochet aux asques mais on ne voit pas bien si le haut des asques est parfois carré (en vue latérale) toutefois les paraphyses fortement capitées font penser que c'est une Orbilia vraie. Je crois que quaestiformis (que je ne connais pas ) est un peu plus large 2-2,5 µm
Je pensais à luteorubella mais sans aucune garantie d'autant que je n'ai pas d'idée pour la conidie.
En attendant Zotto !
Amicalement.
Robert

Good evening alltogether

When I look at your images of asci with spores at 200%, then I see there are much longer filiform spore bodies in the spores than in the enlarged spore on lower right. This means the free spore is either immature or overmature, but not optimum. The upper spore end is subacute which excludes quaestiformis. But I feel the spores have a width of about 2-2.2 µm. My only idea is O. filiformis. This species we have previously merged with O. subtrapeziformis, but we now restrict the latter to high-montaneous collections (above ca. 1200 m) which have broader spore bodies (SBs). The name of the present species is after the filiform SBs in the spores. Either of them is unknown to the literature.

The host spectrum of O. filiformis is presently: Acer campestris {1}, A. pseudplatanus {4}, Acer sp. {2}, Clematis vitalba {2}, Fraxinus excelsior {1}, Juglans regia {1}, Populus canadensis {1}, P. tremula {2}, Prunus spinosa {1}, Quercus ballota {1}, Robinia pseudoacacia {1}, Salix appendiculata {1}, S. caprea {1}, S. caprea x aurita {1}, Salix sp. {1}, Sorbus domestica {1}, Tilia platyphyllos {2}, canes of Rubus ?bifrons {1}.

So it would be the first time on conifer! Patrice, how abundant is your collection? I would very much like to see it, especially because of the deviatng host. You can send it in dry state, the fungus is xerotolerant over several weeks.

O. luteorubella is semiqauatic and has not that slightly curved tail-like spore base, also narrower spores, and apothecia immarginate.

Zotto
Hans-Otto Baral, Evi Weber
Blaihofstr. 42
D-72074 Tübingen

Thank you for all that. I can send this Orbilia on monday. OK ?

Yes, no problem, many thanks in advance. Please let me also know the collection data. Was the branch or trunk on the moist ground? This group of Orbilia with orange apos grows on still attached or standing dead substrate but occasionally they survive some time when fallen to the ground.

Zotto

I have now studied this interesting collection, and I must say that Piotr is right, it is O. quaestiformis, a quite frequent but somewhat variable species. Xerotolerant, and growing on both herbaceous stems and wood or bark of angiosperm trees and shrubs. It is funny that Piotr once had a find which he said is on Picea wood, and that was the first and only case of coniferous substrate. Finally I found that the substrate was Salix. Now, Patrice made the first true conifericolous collection (no doubt about the sbstrate!). However, my first impression was that the spores look a bit strange, and I already considered a new species, because the spores often have a distinct tail, almost like flagellispora. But spore shape is very variable as you can see from my drawing. Regrettably I did not find any conidia. The Trinacrium Patrice has on his photo would be very untypical, we believe that it doesn´t belong to this Orbilia. Evi will also try to find conidia soon. We have an Orbilia coniferarum which is very close to quaestiformis but with other conidia and quite untailed spores, so I am qute sure this is excluded.

Zotto

Here come the conidia. Evi was successful, not many but enough. She also saw a few Trinacrium with basally broadly attachd arms (as on your image), but these surely do not belong to the Orbilia. Our O. quaestiformis culture had exactly these conidia, so we are now sure that your find is typical quaestiformis.

The arms are at the attachment strongly constricted, and usually there are 3 or even 4 arms. The 3-dimensional conidia are difficult to photograph because the arms point in all directions.

Zotto

I forgot to explain the name quaestiformis: not always the character is so frequent as in Patrice' collection: in five of the spores on my sketch the spore bodies form quite distinct question marks.

any questions?
Zotto

Thank you for all that with explanations.