Myxo on grass and bracken: Diderma testaceum?

Please add where and when your myxomycete was found.
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Sheffielder
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Myxo on grass and bracken: Diderma testaceum?

Post by Sheffielder » Mon Oct 09, 2017 9:14 am

On grass and base of bracken in a Sheffield woodland last week. The peridium looks 2-layered to me. Spores are typically 9 um.
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Sarah
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Re: Myxo on grass and bracken: Diderma testaceum?

Post by Sarah » Fri Dec 08, 2017 11:04 pm

Hello Sheffielder,

I find a very similar looking species on moss in northern Tasmania. The spores in my collections are 9-10 um and the capillitium looks similar to yours. Steve Stepheson identified mine as Diderma cf. niveum. I just checked Poulain et al and it seems that the colour of the columella can be diagnostic.

Sarah

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John
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Re: Myxo on grass and bracken: Diderma testaceum?

Post by John » Sun Dec 10, 2017 3:35 pm

I think Diderma niveum can be excluded because of habitat - it is principally a snowline species I believe.

It does look like a peridium with two layers.

According to Ing "the pink, porcelain peridium is distinctive but faded specimens could easily be mistaken for Didymium difforme but the crystalline lime and the ornamented spores of the latter should avoid mis-identification". I can't see any crystalline lime.

Does the peridium look pink "in the flesh"? (It looks like it may have a hit of pink in the first stereo image but looks more ochraceous in the last image).

Another possibility might be Diderma donkii which has an ochraceous peridium. Ing states it is rare but I have a collection that someone sent me last year from the Peak District I think. I will find my records.

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John
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Re: Myxo on grass and bracken: Diderma testaceum?

Post by John » Sun Dec 10, 2017 4:09 pm

Diderma donkii. Collector: Steve Clements, Peak District Aug 2016
Diderma_donkii_1000.jpg
Ing "the distinctive colour and the thickened central portions of the capillitial threads separate this from the other pale, flattened litter-inhabiting species. "
I don't seem to have any micro photos but will see what I can rustle up.

Sarah
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Re: Myxo on grass and bracken: Diderma testaceum?

Post by Sarah » Mon Dec 11, 2017 2:36 am

You're right John, D. niveum is generally regarded as a snowbank species. (My study site does not fit the 'snowbank' description.)

According to N.E. N-B 'D. testaceum is characterised by its usually rosy shade and the gregarious and small sporangia.'
and D. donkii 'distinguished from D. testaceum ... by the duller peridium, the different colour and by its spores.'

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