Lichenicolous fungus on Lecanora polytropa

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Heather P
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Lichenicolous fungus on Lecanora polytropa

Post by Heather P » Sun Dec 08, 2019 11:16 am

I found a pebble with Lecanora polytropa with some apothecia tinged aeruginose and other apothecia blackened but some with the same blue-green tinge.I wonder if this is Carbonea supersparsa or Carbonea aggregantula but I don't have asci or spores, other than a few possible ellipsoid spores 7x3.5 which may or may not be related. Some blackened apothecia show chains of ? condidia. Any thoughts please?
The pebble was at Findhorn, Moray.
Attachments
PC077763.jpg
lecan polytr aeruginose.jpg
margin of apothecia
margin of apothecia
?conidia possibly flask-shaped
?conidia possibly flask-shaped
PC087758.jpg

Neil Sanderson
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Re: Lichenicolous fungus on Lecanora polytropa

Post by Neil Sanderson » Wed Dec 11, 2019 11:26 pm

Heather

I can not help much but the conidia are probably something other than Carbonea sp, as the LGBI2 gives the genus as having "curved, thread-like" conidia. If it is a Carbonea invasion then it is at an early early stage, so may be not identifiable?

Neil
Neil Sanderson

Fay Newbery
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Re: Lichenicolous fungus on Lecanora polytropa

Post by Fay Newbery » Thu Dec 12, 2019 3:10 pm

The dark cells may not be conidia at all. It's very unusual (but not unknown) for conidia to be produced inside the nutrient source of a fungus. The most likely reason for this is that the conidia will not be released until the nutrient source decays. So the photo may be showing melanised hyphal cells rather than conidia.

Neil Sanderson
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Re: Lichenicolous fungus on Lecanora polytropa

Post by Neil Sanderson » Thu Dec 12, 2019 4:11 pm

Fay

Yes looking closely they do look more like melanised hyphal cells

Neil
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Heather P
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Re: Lichenicolous fungus on Lecanora polytropa

Post by Heather P » Sat Dec 14, 2019 3:55 pm

Thanks Fay and Neil.
Please could you explain more about"melanised hyphal cells"?
Heather

Fay Newbery
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Re: Lichenicolous fungus on Lecanora polytropa

Post by Fay Newbery » Sat Dec 14, 2019 6:34 pm

Melanised means that the hyphae have taken on a dark pigmentation (colour). It's very common when fungi want to protect themselves, or their spores, from damaging UV light. Lots of hyphomycetes - fungi that have spores which are not protected inside fruiting structures - are melanised. You may know Xanthoria smut. This fungus grows mainly unprotected on the surface of Xanthoria apothecia so it has dark pigmentation to protect it.

Heather P
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Re: Lichenicolous fungus on Lecanora polytropa

Post by Heather P » Sun Dec 15, 2019 11:24 am

Fay, that's interesting.The example of Xanthoria smut is useful - often growing on the bright yellow side of Xanthoria parietina with it's own sun protection. I don't know of it grows on the grey/ green side of X parietina, when it is out of the sun - I have never looked.
Can anyone tell me whether carbonisation has a similar function.And is this why tips of paraphyses are often dark coloured?

Fay Newbery
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Re: Lichenicolous fungus on Lecanora polytropa

Post by Fay Newbery » Sun Dec 15, 2019 2:44 pm

I think I'm extremely lazy and use the term 'melanised' for any dark structure. But, you're right, I would tend to say 'carbonised' for the wall of a pycnidium or perithecium. Carbonisation also protects from environmental conditions. Maybe from more than UV light. Doesn't carbon insulate well so that it would prevent sudden temperature shifts? Carbonisation probably protects from mollusc grazing too.

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