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27-02-2021 19:00

Nigel Chadwick

Hello I am hoping for some advice about a discomy

25-02-2021 11:37

Castillo Joseba Castillo Joseba

De ayer en bosque de encinas (quercus),  ejemplar

26-02-2021 15:20

Castillo Joseba Castillo Joseba

tambien esta me parece que ya la he visto,  pero

24-02-2021 11:51

William de Jong

Hi,A few days ago I found Helminthosporium velutin

26-02-2021 14:21

Castillo Joseba Castillo Joseba

Recolectada en pasado mertes en caña de gramineaC

24-02-2021 21:56

jean claude chasle

Bonjour,Récoltées sur résidus de taille, pourri

23-02-2021 20:18

Pavol Palo

Hello friends,may I ask you for help ? I would nee

24-02-2021 15:57

Riet van Oosten Riet van Oosten

Hello, Found 20-02-2021 on dead stem of Verbascum

24-02-2021 12:21

Pauline. Penna

Hello everyone I have found these sclerotia on Cy

10-02-2021 20:52

Enrique Rubio Enrique Rubio

On Pseudotsuga bark colonised by abundant lichens

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Roseodiscus ?
Nigel Chadwick, 27-02-2021 19:00

I am hoping for some advice about a discomycete I found on a moorland hill in Lancashire, England at c. 450m, on peat amongst bryophytes - mainly Ceratodon purpureus. I am out of my depth here because I usually study lichens, but I have considered Bryoscyphus, Discinella, Octospora and Ombrophila before finding myself at Roseodiscus formosus.

A rough description:
Apothecia pale pink, 2-5mm diameter with ± flat disc, tapering to a whitish stipe (overall height 3-4mm). Paraphyses c. 2µm wide, septate, not expanded toward their apices, sparsely branched. Asci c. 8µm wide (in KOH), 8-spored, with hemiamyloid apical ring (orange in IKI before treatment with KOH, blue after KOH), with croziers. Ascospores 0-1 septate, 11-18 x 3-4µm (in water), with lipid droplets.

I think my only reservation is that the paraphyses in water appear minutely granular, at least in the living state, but the contents more or less clear in KOH, apart from what looks like an occasional lipid droplet. Any words of wisdom will be gratefully received.

Best wishes

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Hans-Otto Baral, 27-02-2021 20:19
Hans-Otto Baral
Re : Roseodiscus ?
Hi Nigel

clearly R. formosus in my opinion. In your pics I cannot seen the paraphysis contents, are you sure you saw the granules in living ones?

DirkW, 27-02-2021 22:16
Re : Roseodiscus ?
hi nigel, haven't  seen it for a long time. is it the first record in britain? did you recognise our paper on this species? its online.

best regards

Nigel Chadwick, 28-02-2021 09:38
Re : Roseodiscus ?
Hi Zotto and Dirk

Many thanks for your speedy responses. All images except the first are in KOH where the paraphyses were more or less clear. I struggled to photograph what I observed but I've attached a cropped section of the first image (in IKI) and part of another image (in water) where I tried to capture the granular appearance. I examined the specimen the day after I collected it.

Dirk - yes, of course. Without your paper I wouldn't have got very far. Roseodiscus isn't covered in 'Microfungi on Miscellaneous Substrates' which was my first attempt to find a name. When I began to search for info about Discinella I soon found your paper. My German isn't good very good so I pasted sections into Google Translate. It is also referenced in the following page which mentions at least one British record. This might be the second record.

All the best

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Hans-Otto Baral, 28-02-2021 09:51
Hans-Otto Baral
Re : Roseodiscus ?
It seems to me that these paraphyses are also dead, like the ascus which is surely dead.

I assume the first record listed there was that by Steven J. Heathcote in Messingham Heath, 21.II.2020. I have images in my folder which Carol Hobart forwarded to me, she made the micros, Steven the field photo. Regrettably the description there is not from this find but a copy of our paper.
Nigel Chadwick, 28-02-2021 10:22
Re : Roseodiscus ?
I see. I naively assumed that freshly mounted material would have living cells. Now I understand my mistake.

Thanks again for your help - hugely appreciated.

Hans-Otto Baral, 28-02-2021 11:36
Hans-Otto Baral
Re : Roseodiscus ?
A frequent mistake. Of course, KOH kills cells, and also IKI, though tardily. But also pressure on the slide. best is trying sections because then it is easiest to avoid any pressure.