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François BartholomeeusenDear forum members, On the 2nd of February 2026,
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Alain GARDIENNET
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Miguel Ángel Ribes
Good eveningThese small, amphora-shaped perithecia
Hypoxylon on Quercus robur bark
Enrique Rubio,
20-01-2012 18:45
Hi 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
Yannick Mourgues,
20-01-2012 19:10
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
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
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
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
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
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
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
Merci de ton aide
Enrique