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14-07-2025 11:20

Michel Hairaud Michel Hairaud

Bonjour, Voici une espèce de  (?) Hyaloscyphace

16-07-2025 17:34

Bernard Declercq Bernard Declercq

Hello,I have trouble distinguishing above mention

15-07-2025 13:27

Angel Pintos Angel Pintos

Hello, does anyone have access to the following ar

16-01-2023 21:31

Riet van Oosten Riet van Oosten

Hello, Nearby the find of Calycina claroflava on

14-07-2025 17:55

Yanick BOULANGER

BonjourAutre dossier laissé en suspendJe viens de

14-07-2025 11:17

Yanick BOULANGER

BonjourJ'ai un dossier Jackrogersella qui est rest

14-07-2025 15:52

Gernot Friebes

Hi,I wanted to share this collection on Rubus idae

14-07-2025 13:37

Gernot Friebes

Hi,do you think this collection could be R. ulmari

25-02-2023 18:36

Elisabeth Stöckli

Bonsoir, Trouvé sur un tronc de Salix recouvert

12-07-2025 16:45

Thierry Blondelle Thierry Blondelle

Bonjour à tous,J'avais d'abord pensé à des stro

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Black pulvinate asco on Prunus
Ethan Crenson, 26-08-2017 15:56
In the Green Mountains of Southern Vermont, US.  Black pulvinate fruiting bodies 1-3 mm by 1-2mm, sometimes converging into larger forms.  They don't appear peritheciate.  Asci are 102-141 by 12.5-15µm, IKI-.  Paraphyses (not adequately illustrated with my photos) are filiform, some tapering at the ends.  Spores ellipsoid to inequilateral ellipsoid, hyaline with oil droplets, 15.5-18.5 (22) by 5-7µm.  In cotton blue some appear 2-septate.  In KOH they exude deep red pigments.  Thanks in advance for your input.
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Hans-Otto Baral, 26-08-2017 16:08
Hans-Otto Baral
Re : Black pulvinate asco on Prunus
Hi Ethan
Remarkable fungus! I am not sure if the asci stand in a hymenium at the surface of these ascomata or if they are in cavities, i.e., perithecia in a stroma. Do you have survey photos of a section that perhaps show such cavities?

The ionomidotic KOh reaction reminds of a Codieritidaceae

Zotto
Ethan Crenson, 26-08-2017 22:10
Re : Black pulvinate asco on Prunus
Zotto,

In the fourth photo I tried to show a cross section of two ascomata.  As you can see there is a distinct dark layer at the surface and light brown tissue in the interior.  However, I don't detect perethecia in the black layer.  I am including a closer version of one of the section photos here. 

I can't find Codieritidaceae in Google. If there's a typo, I'm afraid I can't figure it out. 

Ethan
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Hans-Otto Baral, 26-08-2017 22:18
Hans-Otto Baral
Re : Black pulvinate asco on Prunus
Sorry, it is Cordieritidaceae. It is a vast group of encoelioid discomycetes.
I would prefer doing a thin section for transmitted light, and also to show the paraphyses.

It may be important too to look whether the ascus tip gets thick-walled in the dead state (after shortly heating the slide or adding MLZ or KOH).
Ethan Crenson, 26-08-2017 22:27
Re : Black pulvinate asco on Prunus
Perhaps these are a little clearer.  I am prepareing to do a thin section as you suggested.
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Hans-Otto Baral, 27-08-2017 07:20
Hans-Otto Baral
Re : Black pulvinate asco on Prunus
Yes, it looks like a hymenium covering the whole exterior. I see dark olive dots on the hymenial surface which probably represent exudate on the paraphysis tips, could you supply  a photo with oil immersion showing thse tips? I assume in KOH this exudate gets dissolved as well?

What also shows the ionomidotic reaction is the genus Dermea. This should contain crystals in the medulla and angular cells in the ectal excipulum.
Ethan Crenson, 29-08-2017 06:51
Re : Black pulvinate asco on Prunus
Otto,
Yes, the exudate on the paraphysis tips dissolves in KOH.  In the photos provided here you can see the paraphyses, both covered in the exudate and naked.  I've also tried to find the features of asci in the dead state and the exipulum that you mentioned, but I'm not sure if I succeeded.
Thank you for your help,
Ethan
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Hans-Otto Baral, 29-08-2017 07:34
Hans-Otto Baral
Re : Black pulvinate asco on Prunus
Yes, this looks good enough to make up one's mind. The apical thickening of the asci is clearly visible, also I think I see many crystals in the excipulum. The latter would clearly exclude a Cordieritidaceae and support that this is a Dermea.

When I go with Groves' (1946) key in Mycologia 38: 364, then I arrive at the common Dermea cerasi.  Ascus and spore size fits well (dead asci in KOH are certainly smaller than the living ones you have measured). Only the anamorph is missing, but anyway I am sure.

Zotto