Ascus reaction is in IKI (euamyloid).

Sp. *24-33 x 10.5-11.5 µm

Hi Zotto,
nice finding! Amphirosellinia is a possible match but first you should assess the situation of the ascomata, superficial or partly immersed. The ascospores you have fit well A. nigrospora but not their colour, they should be blackish. The shape of the germ slit is not very clear on your photo. Is is sigmoid, that is sinuous on one side of the spore, or spiralling around the spore? It cannot be seen clearly on a photo, it needs focusing at different planes when spiralling.
I am sending you the pdf of the Amphirosellinia paper, where you will find a key to related genera.
Cheers,
Jacques

Hi Jacques

thanks for the pdf. The perithecia or stromata are erumpent, yes, the bark covers the whole flanks as you can see on my rather thick sections.

interestingly the asci are horizontally oriented within the perithecium.

Yes, the germ slit is helicoidal, but seems not to reach from one ond to the other. At least sometime I saw that it is interrupted in the middle, so as another germ slit starts very close and parallel to the one. What you mean with sinous is not clear to me, however.

So witz the generic key I quite clearly arrive at Amphirosellinia.

Zotto

I agree Amphirosellinia could best accomodate your finding but it might be a new species. Cultures would be helpful. As I cannot help you further I suggest you to contact Yu-Ming Ju, his email address on the Mycologia paper is still valid.
Cheers,
Jacques

Dear Jacques

I wrote to Yu-Ming recently, and the answer was that it should well be an Amphirosellinia rather than Helicogermslita, but not A. nigrospora because the spores are in my fungus much less dark coloured. Perhaps a new species. So I intend to send the sparse material for culture and sequencing.

Zotto

Hi Zotto,
thanks for letting me know Yu-Ming's positive answer. A very nice find, congratulations!
Jacques

Hello,
this finding also looks like Rosellinia gaudefroyi Fabre and Anthostoma vincensii Arnaud. Both have an helicoidal germ slit and were dicovered on Quercus pubescens. Spores size agrees. (see Laessoe & Spooner, Kew B. 49(1) p. 50 s. n. Helicogermslita)

Bonjour Jean Paul,
content d'avoir de tes nouvelles et bienvenue sur Ascofrance. Tu as raison les similitudes entre la récolte de Zotto et celles de Fabre et de Brunaud sont frappantes, on a certainement affaire au même champignon.
Affaire à suivre!
Amitiés,
Jacques

Dear Jean-Paul

thank you very much for this help. I now wrote to YuMing Ju because I did not yet get a result from him. I told him your opinion, so we will see. I fear I would have much work to trace descriptions of these species.

Zotto

Dear Zotto

I invoice to you by e-mail the original description of "Anthostoma" vincensii by Arnaud (1925 !).
I try to scan the original description of Rosellinia gaudefroyi (1878 !!) and the more recent articles of Laessoe & Spooner (Kew Bulletin).
These (or this ?) species are certainly very very rare.

Jean Paul

Hello Zotto,
Arnaud's original publication (1925 série10 tome VII page 643) is dowloadable here :
http://bibdigital.rjb.csic.es/spa/Volumenes.php?Libro=1851
Regrettably, that of Fabre is absent (1878 tome IX)

Jean Paul

References for the pages of the article of Laessoe & Spooner :
T. Laessoe & B. M. Spooner : Rosellinia & Astrocystis (Xylariaceae) new species and generic concepts
Kew Bulletin 49(1) pp1-70

Jean Paul

... and the date : 1994

Dear Jean Paul

many thanks. I did not yet compare exactly, only had wor with downloading (I prefer JPG which needs 1/5 of the space of the present pdfs).

I am not sure whether this fungus is really rare. It grew on a living standing tree, on the bark among lichens, and I fear that nobody searches there for fungi, except for lichenologists. Similarly, Proliferodiscus tricolor has been overlooked for 100 years. See attach, from this spot where Guy points originates the piece of bark with Amphirosellinia.


Zotto

Dear Zotto

You are right. Mycologists should look more often on the still standing trees !
Interestingly, Fabre doubtless collected his Rosellinia gaudefroyi on a trunk of still standing Q. pubescens : "In cortice duriori, ad basim truncorum Quercus pubescentis."
Available for cosultation here : http://gallica.bnf.fr/ark:/12148/bpt6k5518239h.image.f82.langFR

I got today an answer by YuMing. I hope he is not angry when I paste his mail here. I did not yet check the details about possible differences:

Your fungus is slow-growing, producing only hyphae thus far. I will keep an eye on it until the culture dries up. After our new year break, I will try to grow more mycelia and have it sequenced, and see where it belongs phylogenetically in the Xylariaceae.


Yu-Ming Ju:
Thanks for informing me the comments made by Jean Paul Chaumetonle! Rosellinia gaudefroyi Fabre and Anthostoma vincensii Arnaud were considered in synonymy by Laessoe and Spooner in their 1994 paper and, I think, this fungus is likely a Helicogermslita and may be accepted as H. gaudefroyi, which has equilateral ascospores and a spiraling germ slit. (Note that Laessoe and Spooner recorded the ascospores as inequilateral but illustrated them as equilateral!) Your fungus is however different in having inequilateral ascospores and a sigmoid germ slit that never spirals around the ascospore. I still believe that it represents an undescribed Amphirosellinia species. I hope that you will come up with an ample collection of this fungus which can be used to serve as the type material.
----

The locality is perhaps 500 km away from here, so I will not have further opportunities.