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19-01-2021 15:09

Khomenko Igor Khomenko Igor

Hi, On spruce (Picea) needles, small, white disco

20-01-2021 12:29

Castillo Joseba Castillo Joseba

me mandan el material seco, recolectado en Galicia

14-01-2021 18:36

Edvin Johannesen Edvin Johannesen

Apothecia up to 0,5 mm, on decayed wood of Populus

20-01-2021 20:00

Garcia Susana

Hola, Estoy buscando la descripción de Mycosphae

19-01-2021 10:27

Enrique Rubio Enrique Rubio

Could this synnematous hyphomycete be a Spiropes s

14-01-2021 17:08

Malcolm  Greaves Malcolm Greaves

A large group of what I expected to be Peziza were

20-01-2021 19:56

Enrique Rubio Enrique Rubio

Perithecia non stromatic, clypeate, inmersed under

20-01-2021 15:58

Juuso Äikäs

Last February I found these fungi growing on a fal

06-01-2021 21:01

Andrew N. Miller Andrew N. Miller

Dear Friends,  I would like to obtain a collectio

20-01-2021 11:04

Marek Wolkowycki Marek Wolkowycki

Bialowieza Forest, on dead fruiting bodies of Skel

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Aff. Heterosphaeria on Populus tremula wood
Edvin Johannesen, 13-01-2021 19:14
Edvin JohannesenI though I'd just ask you about this tiny discomycete, which I struggle with. It is only about 0.2-0.4 mm in diameter. It was growing on a Populus tremula log, directly on the wood. The wood is hardly decomposed and very firm. It was collected last May, but I only recently received the dried specimen. It seems like the hymenium in many of the apothecia are now eaten by insects or have decomposed. Thus quite difficult to make nice, thin sections, so I apologise for that.

I am not even sure what family we're in. Initially, when I saw it in wet condition, I thought it was erumpent and was thinking Coccomyces or along those lines. Indeed some of the younger ascomata appear to be erumpent, but in the dried material I see that the dark-rimmed, somewhat dentate apothecia are sitting directly on the wood, anchored by a fringe of white hyphae (anchoring hyphae/subiculum). The hymenium is, when fresh whitish, when dry more greyish and somewhat pruinose.

The spores measure 12-15 x 5 microns, mostly 3-septate, hyaline, smooth. Some spores are smaller (7 x 4) and 1-septate. Many spores are germinating from one or both ends – I guess the specimen is over-mature. What I think are paraphyses are orange-tipped (irregularly flame-like). There are dark, transversely roughened hyphae in the excipulum (fringe) and some spherical cells in what may be subhymenium. The ascus tips are IKI+ (blue in Baral'sche Lösung with no KOH pre-treatment). Structures in the excipulum are stained greenish-blue with IKI, too, but I am not sure that it's due to amyloidity.

Here's a link to some photos. Photo names indicate the medium (KOH, IKI, PC (phase contrast)).

The best fit is in the genus Heterosphaeria, but I'm not sure if any species in that genus grows on wood.  Are we in Phacidiaceae?

Suggestions appreciated.  Thanks!  (I hope the link works)

Hans-Otto Baral, 13-01-2021 21:43
Hans-Otto Baral
Re : Aff. Heterosphaeria on Populus tremula wood
Too overmature to say much. Durella (Xylogramma) atrocyanea would be inamyloid. Any idea of the paraphyses?
Edvin Johannesen, 13-01-2021 22:13
Edvin Johannesen
Re : Aff. Heterosphaeria on Populus tremula wood
Difficult to find an intact hymenium. I thought maybe the three phase contrast images showed paraphyses with the golden structures apically. I will try again to see if I can find intact hymenium with paraphyses, but several attempts have failed so far.