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30-04-2025 01:29

David Chapados David Chapados

Hi, I found Dactylellina candida/candidum, recent

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Louis DENY

Bonjour forumVosges du sud, ballon d'Alsace altitu

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Thomas Flammer

Substrate: Angelica sylvesrisSpore mass: 8.4 - 11.

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Zuzana Sochorová (Egertová) Zuzana Sochorová (Egertová)

Dear mycologists,could someone give me an advice a

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Robin Pétermann Robin Pétermann

Bonjour, Voici une probable Mollisia, genre que j

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Dragiša Savic

Hello everyone,the lichen is Candelariella aurella

27-04-2025 15:54

Martin Bemmann Martin Bemmann

Can somebody provide this article from a Leningrad

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Lennert Gees

Greetings!For my master's dissertation I work on c

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Jacques Fournier Jacques Fournier

J'ai le regret d'informer les membres du forum qui

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Francois Guay Francois Guay

I found these small Arachnopeziza sp. growing on d

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Hypoxylon on Quercus robur bark
Enrique Rubio, 20-01-2012 18:45
Enrique RubioHi to all:

I have collected this Hypoxylon species that grows on Quercus robur bark, at 150 m of altitude, with pulvinate, coalescent and purplish grey stromata. KOH extractable pigments are chlorinaceous-olive. Asci IKI and Mlz. blue. Ascospores with a spore-lenght, straight to sigmoid, germ slit. Perispore dehiscent in KOH 10%.
The stromata seem to have ochraceous granules just beneath the surface.

Maybe Hypoxylon porphyreum or only an Hypoxylon fuscum?.
Many thanks again for help me
Enrique
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  • message #17147
  • message #17147
  • message #17147
  • message #17147
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Yannick Mourgues, 20-01-2012 19:10
Yannick Mourgues
Re : Hypoxylon on Quercus robur bark
Bonjour. Entre les deux, ma préférence irait vers Hypoxylon porphyreum.
Par contre, sur mon écran, la couleur de la réaction dans KOH sur ta photo est jaune ? Qu'en est-il vraiment ?
Yannick
Enrique Rubio, 20-01-2012 19:37
Enrique Rubio
Re : Hypoxylon on Quercus robur bark
Bonsoir Yannick:
La couleur du papier est ocracée mais avec des nuages olive aussi. Il nèst pas jaune pure.
Enrique
Jacques Fournier, 20-01-2012 20:46
Jacques Fournier
Re : Hypoxylon on Quercus robur bark
Hola Enrique,
it is hard to tell but H. porphyreum might indeed be the best match. The KOH reaction appears yellow because it is recorded on paper, on which the yellow fraction migrates first, it is in fact a basic chromatography. On your photo the colour just around the fragment of stroma is brownish, more in agreement with can be expected from H. porphyreum. I suggest you try to record the coloured reaction in a drop of KOH on a slide on a white background, the result should be easier to interpret.
If you have enough material I would be happy to see it, thanks!
Cheers,
Jacques
Enrique Rubio, 22-01-2012 19:07
Enrique Rubio
Re : Hypoxylon on Quercus robur bark
Merci Jacques. Je vais t'envoyer un petit morceau de mon récolte. Mais il tres petite.
Merci de ton aide
Enrique