NEW RARE OR CRITICAL LICHENS 20-5 



Artro valley (-iS), Llanberis, Capel Curig and Cvvm-y-glo (49) and 

 Loch Gal, Kerry. 



P. xanthomyela Nyl. Loch Gal, Kerry (T. Hebden). 



P. revoluta Flk. is not uncommon in Somerset. It occm's on 

 rocks but is more frequent on trees, especiall}^ birch and beech, but 

 sometimes on sycamore, ash, oak, larch, etc. Bi-aunton, c. fr. (4), 

 Exmoor and Quantock Combes (5), Kingsettle hill and Becking- 

 ton (6), Loch Gal, Kerry (T. Hebden), — Form minor Harm, 

 Cricket St. Thomas, Blackdowns and Quantocks (5). — Var. riiqosa 

 (Tayl.) Cromb, Kingsettle hill (6). 



P. tiliacea (Hoft'm.) Ach. On tree-trunks. Castle Neroche and 

 Milverton (5). 



P. omphalodes var. panuiformis Ach. appears to be only a form 

 more or less confluent with the type and similarly somewhat variable 

 in colour. Ashburton (8j, Llanberis (49), Keighlev (J6'd), Tyndrum 

 and Killin (SS), Ben Doran (98). 



P. diibia (Wulf.) Schaer. is P. Borreri of many authors. Lichen 

 duhius Wulf. (1790) antedates Turner's specitic name of Borreri 

 (1808). Plants grown in the shade are often of a j^ello wish-green 

 colour and, to the casual observer, look like small specimens of 

 P. caperata. 



P. exasperata (Ach.) Xyl, is of less frequent occurrence than the 

 numerous records imply, 



P. fuUginosa var. IcBtevirens (Flot.) Nyl. is not uncommon on 

 trees. The form in which the isidia are scarce or absent is var. 

 glahratula (Lamv.) Oliv. (= form denudata Cromb.). Quantocks 



(5)- 



P. pliysodes form tuhulosa (Schaer.) Mudd is a more distinct 

 form than lahrosa, but there does not seem to be any justification for 

 raising it to specific rank as Bitter has done ; even a varietal status is 

 questionable. It is fairly frequent in Somerset and in other parts of 

 the countr}^ — Yar. platypJiylla Ach. is not uncommon in Somerset, • 

 and I think ought to be considered as a form. 



Xanthoria parietina form virescens Nyl. and form cirierascens 

 Leight. are not uncommon states. They are occasionalh^ met with in 

 Somerset. Both these states are included in form chlorina Malbr. 

 and are usually found in more shaded ^^laces than the type. 



Physcia pulvertdenta (Schreb.) Nyl. is a much less common 

 plant than P. aipolia var. cercidia. — Foi-m deminuta Cromb. 

 Orchard Portman (5). — Yar. suhvenusta Nyl. Braunton (4), 

 I'aunton district (5). 



P. farrea (Ach.) Wain. Form pifyrea (Ach,) Wain, is the 

 common form often known as P. pityrea. Form cdpliipliora (Ach.) 

 Harm, is less common and has a white and pruinose thallus. On a 

 brick wall, Norton Fitzwarren (5). 



P. tenella (Scop.) Arn. ( = P. lepdcdea var. ienella Oliv.). 

 Form sulhreviata Xyl. is a less hooded and more sorediate form. On 

 tree, Norton Fitzwarren (5). Form exempta Th. Fr. is considered by 

 Wainio to be a squamiform and corticicolous form of P. trihacia. 

 Crombie (Br. Lich. i. p. 313) mentions that Bon-er referred the 

 specimen to P. erosa, and this is placed by Wainio under P. tri- 

 hacia. 



