21-12-2024 12:45
Marc Detollenaere
Dear Forum,On naked wood of Fagus, I found some ha
23-12-2024 18:18
Rot BojanHello!I've been working with this small fungus for
23-12-2024 12:10
Bernard CLESSE
Bonjour à toutes et tous,Pourriez-vous m'aider à
17-12-2024 12:33
Lothar Krieglsteiner
this fluffy anamorph was repeatedly found on decid
22-12-2024 10:19
Simon Gurtner
Hello,can anyone help me identify this small ascom
22-12-2024 10:53
Bernard CLESSE
Pourriez-vous me confirmer ma détermination de ce
20-12-2024 17:32
Louis DENYBonsoir forumTrouvé à Belfort, 400 m altitude, s
Melanomma?
Hans-Otto Baral,
20-08-2010 13:11
HiIn Middle-Sweden (Saxnäs) grew a bitunicate pyreno on Sorbus aucuparia standing branch together with Orbilia aristata etc. I compare ist with Melanomma but the spores are hyaline, apparently they are ejected when 1-septate, but get more septa when older, still remaining hyaline. Many perithecia are overmature but some are o.k.
Zotto
Hans-Otto Baral,
20-08-2010 13:14
Re:Melanomma?
1-septate Spores ca. 15-18 x 6-6.5 µm, overmature 17-23 x 7-8.5 µm
Hans-Otto Baral,
20-08-2010 13:15
Re:Melanomma?
The small tree was dead because of too much shade.
Hans-Otto Baral,
23-08-2010 10:03
Re:Melanomma?
Section of perithecium
Hans-Otto Baral,
23-08-2010 10:04
Re:Melanomma?
near ostiole
Hans-Otto Baral,
23-08-2010 10:06
Re:Melanomma?
perithecia attached by a short stipe
Hans-Otto Baral,
07-09-2010 22:54
Re:Melanomma?
I've sent my images to Walter Jaklitsch, and he has an idea:
"I collected this fungus several times on about 10 different, unrelated hosts including Spiraea. Some of my specimens were examined by Andre Aptroot, who determined them as Dothidotthia ramulicola (Peck) M.E. Barr. I think one of them was also confirmed by Barr as this fungus. I do not think that they were right, because Dothidotthia has broad, nearly ellipsoid asci with biseriate ascospores, while Otthia has cylindrical asci with uniseriate ascospores, similar to your specimen, where perhaps the spores are not strictly uniseriate.
Anyway, I think that your fungus is Otthia spiraeae (there may be several species hidden under this name ??), immature and aberrantly developed. It seems that ascospores develop very slowly in this species and that unfavourable conditions disturb their development, leaving them in a certain stage without chance of maturing. When mature, ascospores of Otthia spiraeae are about (17-)21-28 x 11-13(-15) µm, very dark brown, 2-celled, with or without various combinations of delicate secondary septa; the 2 cells may be grossly muriform; when hyaline they are 16-23(-25) x 7-9 µm and also develop quite strange combinations of septa, as you show in one of the images. I collected specimens with hyaline ascospores from December to April, so this kind of development may be correlated with low temperatures, or let´s say development is retarded or stopped by low temperatures (?).
Also the ascomata in your images are exactly what I have seen, often with a pallid or dark and stellate ostiolar area in the same specimen.
Interestingly, Barr descibed additional/secondary septa for D. ramulicola
and also ascospore size (of the hyaline spores) fits better. So, in absence
of an anamorph, and if the asci may not be so important, one could also
think of D. ramulicola."
"I collected this fungus several times on about 10 different, unrelated hosts including Spiraea. Some of my specimens were examined by Andre Aptroot, who determined them as Dothidotthia ramulicola (Peck) M.E. Barr. I think one of them was also confirmed by Barr as this fungus. I do not think that they were right, because Dothidotthia has broad, nearly ellipsoid asci with biseriate ascospores, while Otthia has cylindrical asci with uniseriate ascospores, similar to your specimen, where perhaps the spores are not strictly uniseriate.
Anyway, I think that your fungus is Otthia spiraeae (there may be several species hidden under this name ??), immature and aberrantly developed. It seems that ascospores develop very slowly in this species and that unfavourable conditions disturb their development, leaving them in a certain stage without chance of maturing. When mature, ascospores of Otthia spiraeae are about (17-)21-28 x 11-13(-15) µm, very dark brown, 2-celled, with or without various combinations of delicate secondary septa; the 2 cells may be grossly muriform; when hyaline they are 16-23(-25) x 7-9 µm and also develop quite strange combinations of septa, as you show in one of the images. I collected specimens with hyaline ascospores from December to April, so this kind of development may be correlated with low temperatures, or let´s say development is retarded or stopped by low temperatures (?).
Also the ascomata in your images are exactly what I have seen, often with a pallid or dark and stellate ostiolar area in the same specimen.
Interestingly, Barr descibed additional/secondary septa for D. ramulicola
and also ascospore size (of the hyaline spores) fits better. So, in absence
of an anamorph, and if the asci may not be so important, one could also
think of D. ramulicola."