micros

Hi Gernot

if you add Melzer you will very well see the place where the septa are (or keep a flame shortly under the slide to heat the water). Because of the oil drops the septa are indistinct, and in the dead state plasma and oil form one body for each cell.

Zotto

Hi Gernot,
I have no idea about yout fungus. The perithecia seem to have a broadly porate ostiole, somewhat unusual in unitunicate ascomycetes. Can you make sure there is not a broken beak which left this depression on top? A vertical section of the ascoma and measurements of wall thickness might be helpful too. Hope someone will have more insight.
Cheers,
Jacques

Hi Zotto and Jacques,

I tried with Lugol but still the septa were not well visible. However, I didn't think of Melzers, maybe because I always have in mind: "Ascomycetes: Lugol und not Melzers"

There was no beak on the perithecia. I will try to make a section but I never managed it before with such tiny fungi. But I will try :)

Best wishes and thanks for your responses,

Gernot Friebes

Lugol does not kill the spores, so it is necessary to shortly heat the slide. These inconspicuous septa are a problem in living spores.

I have a similar collection of which I made a drawing in 1976 (!). On wood of Carpinus branch. By the way, do there exist indeterminable trees? ;-)

The spores were *33-38 x 4-4.5 µm, slightly curved, but with large and small drops. Likewise I did not see the septa, and I regret I did not keep the material. It is very probable, however that I later found such a species again, but maybe I did not make notes.

Zotto

Hi again,

before going to bed I made a section of a small perithecium, I hope it isn't too bad. The wall is 20-25 µm thick and smooth (the "warts" are algae) and for the spores (now with Melzers, it really works better) I counted (5)7-8 septa. I hope it helps!

@Zotto Well, for me an indeterminable tree is a tree in a mixed forest which you could break with one hand because it is so decayed. :)
But other than that there are many Carpinus around so it could be possible, that the substrate is Carpinus too.

Best wishes,

Gernot

I looked at my old specimen and made some photos. I think it could be the same species. Here is my description when it was alive (spores were multiguttulate):

Luxembourg, Manternach, Fielsmillen, Kaleberg,MTB 6204/4, 190m, muschelkalk, on rotten stem of Fraxinus excelsior (wood), 12.III.1989, G. Marson,(HB 3693b). - Assoc.: Brachysporium , Cistella "fraxini". - Schluchtwald, ca. 10cm dick, lieg., entrindet, mit pleurok. Moos.

Perith. assoc. with loose black setae of Brachysporium sp., partly on perithecia!, globose/acute-conical, solitary, scattered, superf., ca. 0,2 mm diam. Sp. longfusoid, somet. falcate, CRB-, *29-34 x 2,5-2,9 µm, lipid content 5, hyaline, 3-septate (septa distinct only when dead), not constricted at septa, 4 nuclear areas, multiguttulate (large LBs ca.1 µm & minute LBs), Asci with small apical ring (1,5 µm diam.), IKI-, no wall thickenings.

In 1989 I identified as "Chaetosphaeria sp.".

Zotto

Hi Zotto,

thanks for having a look at your old specimens! It looks quite similar to my collection, however, your spores seem to be constantly 3-septate. But other than that I think that at least the genus could be the same.
Do you or maybe someone else know good literature for Chaetosphaeria? Martina Réblová made some studies in Chaetosphaeria s.l. but I don't find anything about Chaetosphaeria s.str.

Best wishes,

Gernot

Hi Gernot,
several species of Chaetosphaeria indeed have similar ascospores, but ascospores and their guttules are not all!
The ascomata of Chaetosphaeria are small-sized, for example those species with large ascospores as yours average 200-250 µm diam, not 600 µm like you report, and they are associated with an hyphomycetous anamorph present on the substrate but also often on the ascomata. According to Martina Réblova, any safe identification of Chaetosphaeria should rely on the anamorph either obtained in culture or present around ascomata.
A paper you should get is: The genus Chaetosphaeria and its anamorphs, Martina Réblova 2000, Studies in Mycology 45: 149-168. Sorry I don't have it as a pdf.
Best wishes,
Jacques

Hi Gernot & Jacques

you are right, I overlooked the more septa in your fungus. My spores are perhaps also a bit more fusoid. I have another one with about 15 septa, if you like :-)

I have some pages of Reblova 2004 with a big key, maybe that helps. But there the anamorph is soon asked for.

plate

http://www.cbs.knaw.nl/publications/sim-45/content/pdf/141-148.pdf

key p. 1

key p.2

key p. 3

key p. 4

Hi Jacques,

"several species of Chaetosphaeria indeed have similar ascospores, but ascospores and their guttules are not all!"

I said "at least the genus COULD be the same" but after having received the paper by Martina Réblová from Alain (thanks to him!) I don't think it's this genus anymore either. So I never were sure my find was a Chaetosphaeria, and off course I would never give my find a name before having read the monograph by M. Réblová.

It will now be one of the many pyrenomycetes without a name, I can live with it by now ;)

Best wishes,

Gernot

celui de 2004
http://www.cbs.knaw.nl/publications/1050/017-Four%20new%20species%20of%20Chaetosphaeria%20from%20New%20Zealand%20and%20redescription%20of%20Dictyochaeta%20fuegiana.pdf

oh, while writing my answer to Jacques you uploaded the key - thank you Zotto and Guy! But still, there was not an anamorph around the perithecia and therefore I don't think an identification will be possible - provided that it is a Chaetosphaeria at all.

Another one with 15-septa? Well, you never can see enough pyrenomycetes, so if you don't mind showing it I'd ask you for it!

Best wishes,

Gernot

here you have it. My data (sorry, I did not measure much):

HB 6170c. Tübingen-Pfrondorf, 400m, on very rotten branch of Quercus (wood), 28.VI.1998, H.-O. Baral & G. Marson (HB 6170c)Assoc.: "Fuscolachnum mollisioides, Durella connivens Waldrand, Hang zur Schlucht, Qu-Carp-Acer camp-Frax-Fag-Wald, ca. 3m above ground, ca. 1m long. branch, near tip, 15-20mm thick, decort., strongly algae-covered. Asci unitunicate, Spores *38 x 5,3 µm, hyaline, strongly fusoid, ca. 14 celled, many minute LBs.

thank you! It looks interesting but it's a pity that pyrenomycetes are the most indeterminable fungi in the world :(

That seems right, and I fear it applies especially to those growing on hanging substrate.