Opegrapha?

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Chris Johnson
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Opegrapha?

Post by Chris Johnson » Sun Feb 03, 2019 5:07 pm

Growing on a rough-barked tree (which I failed to note, so provided an image). Unsure if the silver-grey thallus belongs to the species in question or is a host. Spores (3-septate) become brown quite late into maturity. Spore-drop, in water: 19.9-25.5 x 7.6-9.8 µm. Me = 22.4 x 8.7. The spores are quite wide for this genus, even allowing for shrinkage when measured in KOH.

As you can tell, I failed to key it out so any help appreciated.
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JennyS
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Re: Opegrapha?

Post by JennyS » Sun Feb 03, 2019 5:13 pm

Hi Chris - its a non-lichenised bark fungus, Hysterium or something related. Somewhere I've a link to an on-line key that I'll try and find......
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Re: Opegrapha?

Post by JennyS » Sun Feb 03, 2019 5:18 pm

Jenny Seawright

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Chris Johnson
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Re: Opegrapha?

Post by Chris Johnson » Sun Feb 03, 2019 7:49 pm

Hi Jenny
Ironically, I found a link to Hysterium in Smith et al. but wasn't convinced by the 3 I found on the British list. However, the key is very useful and taken me to Hysterium angustatum which is looking good. I will work through the keys again.
With thanks,
Chris

Neil Sanderson
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Re: Opegrapha?

Post by Neil Sanderson » Sun Feb 03, 2019 8:47 pm

The end cells of the spores appear a bit paler than the others which would suggest Hysterium pulicare, but I do not know these fungi well, so not sure how pale the the end cells need to be.

All the best

Neil
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Chris Johnson
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Re: Opegrapha?

Post by Chris Johnson » Sun Feb 03, 2019 8:57 pm

Thanks Neil.
The spores of Hysterium pulicare are longer and start where mine finish and both end-cells are much paler, so unlikely but still checking.
Best wishes,
Chris

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Re: Opegrapha?

Post by Neil Sanderson » Sun Feb 03, 2019 9:18 pm

Chris

Looking at http://fungi.myspecies.info/taxonomy/te ... scriptions, it does seem more like H angustatum but the text does imply they area not always easily separable.

Neil
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