26 Rev. T. Salwey^s List uf Lichens in Wales. 



Pertusaria crassa. Upon an old tree at Ty Gwyn ; on an old ivy-tree 

 in Cheriton churchyard, Pembrokeshire. 



Thelotrema lepadinum. In great perfection upon old trees at Cors-y- 

 gedol. It grows also upon rocks at Llyn Bodlyn, the only instance 

 I know of its growing upon stone. 



melalcucum. Upon trees at Holyland near Pembroke. 



Lepraria lolithus^. Very finely upon stones about Cors-y-gedol. 



Variolaria lactea. In great perfection about Barmouth. 



terricola. Cwm Bychan, Pont Fadog, &c. 



Urceolaria Acharii. This usually grows upon stones occasionall}' sub- 

 merged, as in rivulets and at the edge of lakes ; but I once found 

 a very beautiful specimen upon a wall in a very high and dry 

 situation, so finely developed in all its parts, that I could for some 

 time scai'cely persuade myself it was not a new lichen. 



Lecidea atrata. Craig Drwg : very scarce. 



atro-alha. Rocks at Llyn Bodlyn. 



fusco-atra. Rocks about Barmouth. 



cechumena, /3 athrocurpa. Rocks behind the Union-house at 



Corwen. 



petrcea. } ^ 



^ ^ > Common. 

 conjiuens. j 



lapicida. Rocks above Gwastad-annos and Llyn Bodlyn. 



promimda. Rocks about Barmouth. 



parasema (not elaochroma, with which it has been con- 



founded). Upon beech-trees near the House at Crafnant, Cors-y- 

 gedol, &c. 



sangidnaria. Upon rocks and old gate-ioosts : not uncommon. 



viridi-atra. Walls and rocks : an obscure and puzzling 



lichen. 



geographica. ~] 



silacea. 



rT^ , . ^Common. 



(Eden. \ 



■ fiavo-virescens.J 



I once found (Ederi in a remarkably high state of development upon 

 a mass of stone, which, upon breaking it, was found to be pi-incipally 

 copjjer ore, to which circumstance undoubtedly the alteration of the 

 plant was owing. 

 scabrosa. Not uncommon, but seldom found in a good state : 



Aberhamfrac, &c. 

 idiginosa. On the road- mud thrown on the top of the wall 



* I liave inserted a species of tlie genus Lepraria because British authors 

 have hitherto, as far aa I am aware, agreed in retaining this genus. I should 

 be glad however to see not only this genus, but also Variolaria, which is 

 almost equally unsatisfactory, rejected altogether from an Eiuuneratio Li- 

 clienum. Wheth'^r Fries is light in considering them as the decaying re- 

 mains of move perfect Lichens, or other authors as the commencement of 

 Lichens which require only more favourable circumstances to become more 

 fully developed, I will not venture to decide, though my own opinion leans 

 to the latter view of the question. The genus hidiuin is jjerliaps equally- 

 unsatisfactory and ought also to be rejected. 



