Bacidina squamellosa

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Neil Sanderson
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Joined: Tue Jan 08, 2019 7:30 am

Bacidina squamellosa

Post by Neil Sanderson » Thu Sep 12, 2019 10:01 pm

Another lichen I found recently on the Elan Valley survey was Bacidina squamellosa (Bacidia squamellosa), new to Radnor. This is probably a widespread oceanic lichen but is still under much recorded. The usually sterile coralloid isidiate thallus looks so very much like Micarea prasina s. lat. that is difficult to pick out, unless fertile, when it has lovely bright yellow disks. I mentioned find pycnidia previously on this site but I have some more pictures from Elan, so I thought I would put some up to encourage recording. Bacidina squamellosa is easily proved by the algae size, they are up to 12 µm diameter while those of Micarea are a maximum of 8 µm diameter. The difficulty is picking out candidates from all that Micarea prasina s. lat.

Look for what look like yellow-green or paler green and shiner versions of Micarea prasina s. lat. on more base rich bark, the shininess is very usefully the lichen is not too wet. In the Eland Valley the Bacidina squamellosa thalli were actually quite noticeable for once.

Bacidina squamellosa thallus

Close view of thallus

Thallus squash showing large algae cells (it needs a good hard squash to make the algae clearly visible)
Neil Sanderson

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