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04-11-2025 12:43

Edvin Johannesen Edvin Johannesen

Hi! One more found on old Populus tremula log in O

04-11-2025 09:07

Josep Torres Josep Torres

Hello.A suspected Hymenoscyphus sprouting on a thi

04-11-2025 14:53

Josep Torres Josep Torres

Hello.Very small, globose, mucronate perithecia, b

03-11-2025 21:34

Edvin Johannesen Edvin Johannesen

These tiny (0.4-0.5 mm diam.), whitish, short-stip

03-11-2025 19:41

David Chapados David Chapados

Hi,Does anyone knows which genus could this be? G

28-10-2025 15:37

Carl Farmer

I'd be grateful for any suggestions for this strik

03-11-2025 16:30

Hans-Otto Baral Hans-Otto Baral

Hello I want to ask you if you have found this ye

01-11-2025 09:14

Francis Maggi

Bonjour,Trouvé sur Xanthoria parietina à Valdebl

28-10-2025 19:33

Nicolas Suberbielle Nicolas Suberbielle

Bonjour à tous,Je voudrais votre avis sur cette r

31-10-2025 09:19

Lothar Krieglsteiner Lothar Krieglsteiner

Can somebody provide me with a file of:Rogerson CT

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Mycosphaerangium tetrasporum ?
Arold Lavoie, 27-04-2014 06:48
Arold LavoieBonjour,

J'aimerrais savoir si selon vous, il s'agit bien de Mycosphaerangium tetrasporum? Voici mes observations :
Apothécie : érumpante dans le bois; disque brun orangé à noir; environ 1 mm de largeur
Asque : 4 spores. Après KOH et solution de Lugol, les asques deviennent rouges entre les spores.
Spores : subglobuleuse, granuleuses, hyalines lorsque jeunes, devenant brun foncé à maturité; 26,2 - 29,8 um de long.
Habitat et substrat : Branche de feuillu au sol. Érablière à hêtre et à chêne rouge. Montérégie, Québec.

Bien que Seaver (1951) rapporte des spores entre 20 et 25 um de long, Cash (1940) mentionne plutôt 22 – 28,5 um de long, ce qui le rapproche de mes mesures.

Voici les liens vers mes photos :
https://www.flickr.com/photos/gnomediscret/14028500055/
https://www.flickr.com/photos/gnomediscret/14025311071/
https://www.flickr.com/photos/gnomediscret/14028948084/
https://www.flickr.com/photos/gnomediscret/14005391336/
https://www.flickr.com/photos/gnomediscret/14025303382/
https://www.flickr.com/photos/gnomediscret/14028513015/
https://www.flickr.com/photos/gnomediscret/14028939934/

Je vous remercie!
Arold Lavoie, 27-04-2014 08:20
Arold Lavoie
Re : Mycosphaerangium tetrasporum ?
Et quelqu'un aurait ce document svp?

Verkley, G.J.M. 1999. A monograph of the genus Pezicula and its anamorphs. Studies in mycology. Vol. 44. 180 p.

Metci!
Hans-Otto Baral, 27-04-2014 10:06
Hans-Otto Baral
Re : Mycosphaerangium tetrasporum ?
Very interesting collection! I see strong similarities to Hymenobolus agaves, a species we had here in the forum. Maybe both are congeneric?

I think it is this species, but I did not compare the other two transferred there by Verkley. 

Zotto
Arold Lavoie, 27-04-2014 17:25
Arold Lavoie
Re : Mycosphaerangium tetrasporum ?
Dear Zotto!

I read the description in Verkley (thanks for sharing!) and it confirms the identification. The only difference I see is that he wrote that the asci are IKI-. The asci on my specimen are clearly IKI+ red, but I've made a pre-treatment with KOH... 

Thank you vey much!
Hans-Otto Baral, 27-04-2014 20:47
Hans-Otto Baral
Re : Mycosphaerangium tetrasporum ?
No, they are IKI-. The iodine reaction of asci refers always to the wall, not the ascoplasm. In your case the ascoplasm reacts red, which indicates the presence of glycogen.

You say that there is Quercus and Fagus around, Didi you look at the broken wood? The distinction is very easy: only Quercus is ring-pored (rapidly visible with a hand lens).

Zotto
Arold Lavoie, 27-04-2014 22:59
Arold Lavoie
Re : Mycosphaerangium tetrasporum ?
I identified the substrate this afternoon. It's a broken branch of Northern red oak (Quercus rubra), a species close to Q. coccinea (on which Ellis made his collect in 1875).

Thanks for the information about the red asci!