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Catathecia

Posted: Wed Jan 15, 2020 3:09 am
by Fay Newbery
Can anyone explain what catathecia are please? The descriptions where I have found the term mention ostioles. So are these perithecia?

Re: Catathecia

Posted: Wed Jan 15, 2020 8:25 am
by Chris Johnson
New one on me too, Fay.

Dictionary of the Fungi says 'catathecium, a flattened ascoma, having the wall more or less radial in structure, and with a basal plate, e.g. Trichothyrina; cf. thyriothecium.'

Chris

Re: Catathecia

Posted: Wed Jan 15, 2020 11:50 am
by Lancashire Lad
To add to what Chris has said, there is an explanation (copied below) in the article: -
"Observations on some genera of Trichothyriaceae: B.M.Spooner & P.M.Kirk, Myclological Research 94 (2): 223-230 (1990)"
which says: -

"The family Trichothyriaceae was established by Theisse (1914), to include genera having in common the form of the ascomata but differing in ascospore characters and the presence of superficial mycelium. The ascomata are flattened and comprise an upper and a lower layer, each one cell thick, composed of radially-arranged brown-walled cells. This form of ascoma was later termed a catathecium by von Hohnel (1917). Asci are arranged radially with their apices convergent towards a well-defined central ostiole. The ostiole is normally papillate and frequently ornamented with dark brown setae of varying form and disposition".

The entire article can be downloaded as a PDF from AcsoFrance: -
http://ascofrance.fr/uploads/forum_file ... 3-0001.pdf

Regards,
Mike.

Re: Catathecia

Posted: Thu Jan 16, 2020 7:51 pm
by Fay Newbery
Thanks Chris and Mike. I think I'm getting there but I would have loved an annotated diagram. Sounds as if these are similar to thyriothecia but less extremely flattened.

Re: Catathecia

Posted: Tue Jan 21, 2020 11:05 am
by Paul Cannon
Rather late in the day, but hope this helps - a catathecium has a melanized lower wall and a thyriothecium just an upper wall, the asci forming on a bed of mycelium immediately over the underlying plant tissue. What this distinction means in evolutionary terms/real life I can't say...

Re: Catathecia

Posted: Wed Jan 22, 2020 9:54 pm
by Fay Newbery
Thanks Paul. That's helpful. So both are quite flat and positioned on the substrate. Both have a melanised top layer with radially arranged cells (around a central ostiole?). The difference between the two is the composition of the hyphae below the asci, specialised melanised hyphal in one and less differentiated hyphae under the other. Hopefully I have a clear picture in my head now.