Search found 8 matches

by Mark Walters
Tue Feb 11, 2020 1:45 pm
Forum: Lichens
Topic: A problematic Parmelia
Replies: 13
Views: 757

Re: A problematic Parmelia

Thanks once again Mark/Neil for your input on this and the advice on chemical testing procedures. Will compare a good X. conspersa when I see one I can only echo everyones comments about how useful it is to have a forum discussion about ID or other aspects of lichen. It really helps with all of the ...
by Mark Walters
Mon Feb 10, 2020 9:26 pm
Forum: Lichens
Topic: A problematic Parmelia
Replies: 13
Views: 757

Re: A problematic Parmelia

Thanks for the additional input Mark and Neil Mark - can confirm the thallus is light grey with no hint of yellowish-green. I had been using a pipette before which drops a rather non-specific glob of reagent on the testing area as you noticed. Used the tip of sharp pointed tweezers this time to drop...
by Mark Walters
Mon Feb 10, 2020 1:16 pm
Forum: Lichens
Topic: A problematic Parmelia
Replies: 13
Views: 757

Re: A problematic Parmelia

Thanks Neil - I did scrape away the cortex to reveal what I think is the white medulla below (beginner so I may be wrong) and applied the chemicals to the white surface. I'll double check though. So there's no chance I could have a Dermatocarpon growing on/in middle of a Parmelia that is underneath ...
by Mark Walters
Mon Feb 10, 2020 11:45 am
Forum: Lichens
Topic: A problematic Parmelia
Replies: 13
Views: 757

Re: A problematic Parmelia

Hi Caz Thanks for the comments. It was the images of Dermatocarpon online which looked most like the inner thallus covered in perithecia with ostioles and helped me identify those. I dismissed Dermatocarpon though because I assumed two species could not intermingle in this way, but maybe you are ont...
by Mark Walters
Sun Feb 09, 2020 11:59 pm
Forum: Lichens
Topic: A problematic Parmelia
Replies: 13
Views: 757

A problematic Parmelia

I'm struggling with this one for some reason. It keys out in Dobson as Parmelia pastillifera but i'm not convinced that is right for a few reasons: 1. The white medulla does not react red with C although it did go a yellow-orange eventually (it also goes yellow-orange with K). parmcreactjpg.jpg 2. T...
by Mark Walters
Tue Feb 04, 2020 10:58 am
Forum: Lichens
Topic: Lichen ID help please - Lecidea lithophila ?
Replies: 4
Views: 383

Re: Lichen ID help please - Lecidea lithophila ?

Hi Chris

Thanks for the welcome and encouragement. Will certainly post up if I hit any problems with ID's or other interesting snippets.

All the best, Mark
by Mark Walters
Mon Feb 03, 2020 8:42 pm
Forum: Lichens
Topic: Lichen ID help please - Lecidea lithophila ?
Replies: 4
Views: 383

Re: Lichen ID help please - Lecidea lithophila ?

Hi Alan Many thanks for pointing out the alternative ID. Having compared a few lithophila and lapicida photos online now the lapicida seems a better fit, particularly the flattened form of the dark apothecia. It is clear that visual identification from photographic records alone of lichens isn’t goi...
by Mark Walters
Mon Feb 03, 2020 5:18 pm
Forum: Lichens
Topic: Lichen ID help please - Lecidea lithophila ?
Replies: 4
Views: 383

Lichen ID help please - Lecidea lithophila ?

Hi I am a beginner with lichen identification (can identify the basics but no chemicals or compound microscope yet). I am leaning towards Lecidea lithophila for this one recorded at Craig Rhiwarth hillfort, Powys, Wales on siliceous mudstones (thin quartz veins) altered by igneous intrusion. The out...