Hi Karl.
I don't think it's Trematosphaeria. Have you seen ascus ? Could you show us a section of the asco ?
I remember Diplodia genus witch has spores like these, but it should be check.
May be someone else will have the good idea.
Yannick

Hallo lieber Karl,


the spores remind me of Amphisphaeria umbrina. I cannot clearly recognize from the picture, how the perithecia are.


Herzlichen Gruß


Hermine

This is most probably Dothidea sambuci
Kind regards, WJ.

Thanks for your answers.
I don't think that it is Diplodia.
Spores of Amphisphaeria umbrina have no constriction.
The tip of Mr. Jaklitsch seems to be the right one.
Can Dothidea sambuci occur on Lonicera? Sambucus and Lonicera are both Caprifoliaceae.
Description and drawing at Ellis & Ellis, page 254, plate 1143, figure 109 fit very well!
I am attaching some photos. The ascomata have a diameter of less than 1 mm.
Dear Hermine, Yannick and Mr. Jaklitsch thank you for your help!?

Kind regards,
Karl

Hi all,
Of course itsn't Trematosphaeria and Amphisphaeria (very different) and  Diplodia (coelomycete), and Walter is right. I suppose with a vertical cut, we should more recognize Dothidea. But your question is good, Karl. I've another one : what is becomen the taxa Dothidea lonicerae ?
Alain

Hello Alain,

the description of Dothidea lonicerae Cooke
(http://www26.us.archive.org/stream/syllogefungorumo14sacc#page/242/mode/2up/search/dothidea?) fits too.
There is another description of Dothidea lonicerae Fr.:Fr. but this  seems to be a taxon on leaves of Lonicera.
I don't know the difference between Dothidea sambuci and Dothidea lonicerae Cooke. 
Now I am confused.
I am not able to make a vertical cut, sorry.
Kind regards,
Karl

Hello Alain and all,

meanwhile a friend communicated to me that Loeffler (1957), the two taxa Dothidea sambuci and D. lonicerae has synonymized.
Amitiés, Karl

To round up the topic:
Loeffler (1957; Phytopathologische Zeitschrift 30: 349–386) reported D. sambuci also from Lonicera, Viburnum lantana, Corylus, Acer. Petrak also from Cotonesater, Kerria, Cydonia, Rhodotypos, Genista, Fraxinus,..

I found it also on Viburnum lantana, Sorbus aucuparia, Juglans and Euonymus. This means that a fungus identical in morphology occurs on various hosts. However, there is no comprehensive phylogenetic treatment, therefore it is still possible that several cryptic species are hidden behind one morphologically conceived taxon. For the time being the fungus can be called Dothidea sambuci.

To find Dothidea I recommend to examine dead branches attached to the shrubs or trees. 
Regards,
WJ.

OK, Dr. Jaklitsch, i will call it Dothidea sambuci, as you propose.

Thank you very much for the complementary informations. 

Best wishes,
Karl

Very well, thanks for these answers.
Alain