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Hi! Found in Sweden. Ascomata with haris, se

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Hi!We observed this hyphomycete growing between le

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Dear forum members,On April 25 2024, I found one f

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Hello, Does anyone know what this is? Found on J

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Hymenoscyphus albopunctus? (=pusillus)
Viktorie Halasu, 29-07-2019 11:16
Viktorie HalasuHallo, 

I've collected a small Hymenoscyphus (about 1 mm, short stalk), ivory white, on skeletized leaves (unidentified), deciduous alluvial forest.
VBs in excipulum, badly visible in paraphyses.
Excipulum = probably t. prismatica. 
Spores without cilia, constricted in the middle. 
H-, IKI+b.

Could it be H. albopunctus? 
Thank you in advance.
Viktorie 

edit: Now I've found out there are H. microserotinus and H. pusillus too, probably not an easy group. 

edit2: This collection was confirmed as H. pusillus by ITS, on F. pennsylvanica leaves.
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Hans-Otto Baral, 29-07-2019 12:07
Hans-Otto Baral
Re : Hymenoscyphus albopunctus?
Hi Victorie
spore size would fit. I earlier thought it is typical f Fagus leaves but apparently not.
The VBs in the paraphyses you probably didn't see because these were not alive.

Is the ample big enough to take an ITS sequence? I have one of my samples, but it is not certain according to the seuencer. Chinese H. microserotinus (5 sequences) is heterogeneous in GenBank but accumulates around H. aesculi, so should include samples with black stipe base and stroma.

the new H. pusillus on Fraxinus pennsylvanica has also a conspicuous black stroma and dark stipe base.

Zotto
Martin Bemmann, 29-07-2019 15:28
Martin Bemmann
Re : Hymenoscyphus albopunctus?
Hi,

Hymenoscyphus albopunctus is originally a North-American species described by Peck as Helotium albopunctum. White 1942 examined the type material. The spores look much more slender as they measure 14-16x3.5-4 µm. One of the other characteristics of H.a. is a very short stipe. White 1943 recorded for the most of the collections he examined a stipe shorter then 1 mm. In the type material it was 0.1 mm.

Regards

Martin
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Hans-Otto Baral, 29-07-2019 17:08
Hans-Otto Baral
Re : Hymenoscyphus albopunctus?
Hi Martin
I see that you made a survey many years ago on this species and my Hym. "fageolus".
Of course it might be that in America a different species occurs, but as long as we have no DNA data, we can hardly decide, because the morphology is not clearly different and stipe lengths vary.
A spore width of *4-4.5 gets +3.5-4 which is what White measured.

Spore size in HB 8596 is *(12-)13-15 x 4-4.5 µm, just as in Victorie's sample.

Zotto
Viktorie Halasu, 30-07-2019 11:48
Viktorie Halasu
Re : Hymenoscyphus albopunctus?
Dear Zotto,

thank you for confirmation. Stipe base is not blackish like in H. aesculi. 
I've found similar one there on Quercus leaves (non skeletized) in late october, but determined as H. caudatus (spores up to 19,1(20) um long, but constricted in the middle). Also Dumont (1981) synonymized H. albopunctus (as "albopunctatus") under H. caudatus. How do you distinguish them? Shorter spore length + presence of centrally constricted spores for albopunctus? 


There are not many apothecia, but I'll put a few aside and try to collect some more. My friend who's doing the sequencing will be available again since autumn, if it works I'll let you know. 
 


Dear Martin,
thank you, I didn't recherche all the relevant literature yet, although it seemed it's not very frequently described/published taxon.


Viktorie

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Hans-Otto Baral, 30-07-2019 16:55
Hans-Otto Baral
Re : Hymenoscyphus albopunctus?
Smaller spores, yes, constriction occurs also in H. caudatus in the sense I use it for a frequent species with a lower lipid content in the spores, and in a low refrcativity of the VBs.