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27-03-2024 22:53

Charles Aron Charles Aron

Hi All,Recently I came across these minute, setose

26-03-2024 17:14

Juuso Äikäs

These little black ascos were growing on a dead, d

25-03-2024 13:41

B Shelbourne B Shelbourne

• Hyaloscyphaceae (no VBs), Hyaloscypha: Macro a

25-03-2024 21:27

Riet van Oosten Riet van Oosten

Hello, Found by Laurens van der Linde, March 2024

26-03-2024 14:37

DAVID MARCOS DAVID MARCOS

Spores (telles qu'elles apparaissent à l'intérie

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Thierry Blondelle Thierry Blondelle

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michel bertrand

Bonjour, Malgré de nombreuses recherches, je n'a

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Ursula Kozik

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25-03-2024 03:56

B Shelbourne B Shelbourne

• Scuttelinia: Macro and habitat.• S. scutella

25-03-2024 20:21

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Bonjour, je m'appelle David et je débute dans l'i

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White ascolichen (?) on burnt ground
Enrique Rubio, 18-03-2019 12:06
Enrique RubioHi to everybody
These minute, white, sessile, pruinose, hemisphaerical, neither applanate nor cupulate, 0.5-0.7 mm in diameter, grew among Ceratodon purpureus and algae on sandy burnt soil.
The thick-walled, strongly dextrinoid asci which may appear to be bitunicate, have an irregular apical dehiscence as in some Mniaeceia species (white arrow). No conspicuous paraphyses I have seen. Ascospores coarsely verrucose.
Some idea for it?
Many thanks again
Enrique
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Hans-Otto Baral, 18-03-2019 12:16
Hans-Otto Baral
Re : White ascolichen (?) on burnt ground
Hi Enrique

superb. The asci are hemiamyloid, not dextrinoid, and I am quite sure this belongs in Vezdaea. No idea about a name, I have no key at hand.

Zotto
Enrique Rubio, 18-03-2019 12:21
Enrique Rubio
Re : White ascolichen (?) on burnt ground
Hi Zotto
Could you  explain to me the differences between hemiamyloid and dextrinoid?
Hans-Otto Baral, 18-03-2019 12:27
Hans-Otto Baral
Re : White ascolichen (?) on burnt ground
This is quite easy: 

dextrinoid is a red reaction that is seen in both Lugol and Melzer (better in the latter), and if you pretreat with KOH it is still red.

hemiamyloid is only red in Lugol, and if you KOH-pretreat, the reaction is blue.

In your Vezdaea surely the asci will react blue after KOH.

Besides, I never met an ascus with an outer wall reacting dextrinoid.

Zotto
Enrique Rubio, 18-03-2019 12:43
Enrique Rubio
Re : White ascolichen (?) on burnt ground
Really I don't see much changes after KOH-pret. Just like it used to be, the basal part is bluer and the apical one is redder.
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Hans-Otto Baral, 18-03-2019 12:50
Hans-Otto Baral
Re : White ascolichen (?) on burnt ground
Did you also test MLZ for whether the red appears?
Enrique Rubio, 18-03-2019 13:08
Enrique Rubio
Re : White ascolichen (?) on burnt ground
Only orange, without any bluish hue, in Melzer's reagent. Blue and reddish colors are present in IKI after KOH-pret. There are bluish and reddish asci.
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Antonio Gómez-Bolea, 18-03-2019 14:48
Re : White ascolichen (?) on burnt ground

Yes is Vezdaea


V. rheocarpa fits well with your sample.

Hans-Otto Baral, 18-03-2019 15:25
Hans-Otto Baral
Re : White ascolichen (?) on burnt ground
I suppose your first KOH-pretreatment was not strong enough. In the second I see only blue ascus walls. Higher KOH-concentrations or a short heating over a flame assure that the chemical conversion takes place.

MLZ without KOH should be negative, I think the orange is due to plasma staining by the colour of iodine.
Enrique Rubio, 18-03-2019 15:48
Enrique Rubio
Re : White ascolichen (?) on burnt ground
Thanks, Zotto and Antonio.
I will look for V. rheocarpa.
Enrique Rubio, 18-03-2019 16:12
Enrique Rubio
Re : White ascolichen (?) on burnt ground
By the way
Has someone the invalid description of Vezdaea rheocarpa Poelt & Döbbeler, Bot. Jb. 96(1-4): 347 (1975)?
Many thanks in advance
enrirubio@asturnatura.com