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09-01-2026 17:41

Arnold Büschlen

Hallo, F. dilatata wird von vielen Bryoparasiten

10-01-2026 20:00

Tom Schrier

Hi all,We found picnidia on Protoparmeliopsis mur

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Danny Newman Danny Newman

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Danny Newman Danny Newman

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Danny Newman Danny Newman

Pezicula sp. on indet. hardwood Appalachian Highl

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Blasco Rafael Blasco Rafael

Hola, en el mismo habitat que la anteriorRetamaDia

08-01-2026 21:22

Blasco Rafael Blasco Rafael

Hola, He recogido esta muestra de Orbilia sobre Re

07-01-2026 17:29

Marc Detollenaere Marc Detollenaere

Dear Forum,On a barkless Populus I found some smal

10-11-2021 17:33

Riet van Oosten Riet van Oosten

Add-on topic http://www.ascofrance.com/forum/7059

07-01-2026 10:05

Danny Newman Danny Newman

cf. Chaetospermum on XylariaCosby Campground, Grea

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Tiny white apothecia on Populus inner bark
Edvin Johannesen, 15-10-2025 16:39
Edvin JohannesenThese tiny (0.2-0.6 mm), white, pulvinate apothecia were found on the inner bark of a fallen Polulus tremula (fallen ca. ten years ago). Spores measure ca. 9-12 x 3 µm, 1-septate. Croziers present (as far as I can judge).  IKI negative (Lugol). Paraphyses difficult to discern in water, but some with guttules seen in Lugol. Spores arranged diagonally uniseriate in asci. Rounded cells in excipulum. I have not been able to see hairs at the margin.

I have no good suggestion. Anyone?
Thanks!
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Hans-Otto Baral, 15-10-2025 17:23
Hans-Otto Baral
Re : Tiny white apothecia on Populus inner bark
Hmm, you have only dead asci, so no wonder when the spores are uniseriate. It may be that fully mature asci contain spores without a septum. Important are the paraphyses: do they contain these guttules also in water? It would be unusual for such a fungus.

I assume the apos are sessile. A possiility could be Hyaloscypha without hairs (earlier called Parorbiliopsis). But the frequent H. minuta lacks croziers. But the paraphyses do not fit when the guttules are there already in water.
Edvin Johannesen, 15-10-2025 17:35
Edvin Johannesen
Re : Tiny white apothecia on Populus inner bark
Thanks, Zotto. I will try to check the paraphyses in water once again. I wonder why asci are dead when the apos are apparently perfectly fresh.
Edvin Johannesen, 15-10-2025 18:05
Edvin Johannesen
Re : Tiny white apothecia on Populus inner bark
Paraphyses are non-guttulate in water, filiform, apparently branched/bifurcate at some points, ca. 1-1.5 µm thick, slightly thicker at the tips. Difficult to see in water (easier with phase contrast).

Yes, apos are sessile. Hymenium convex, so that from the side they're looking somewhat lenticular. They begin to turn slightly yellowish upon drying.

Does this help?
Hans-Otto Baral, 15-10-2025 19:33
Hans-Otto Baral
Re : Tiny white apothecia on Populus inner bark
So you did not see any living asci? It is because of the spore septation. I cannot imagine a Hyaloscypha with septate spores in the living asci.
Edvin Johannesen, 15-10-2025 23:27
Edvin Johannesen
Re : Tiny white apothecia on Populus inner bark
I wish I was able to decide whether asci are living or not.