J'AK.MKLIA.] PARMELIEI. 235 



Hal. On the trunks of trees and on rocks in wooded maritime and 

 mountainous districts. Distr. Apparently very local and rare in S. Eng- 

 land (Danny, Sussex,/* Nyl.), in N. Wales, and the S.W. Highlands, 

 [Scotland. B. M. : Drews-y-nant, Merionethshire. Barcaldine, Argyle- 

 shire. 



3. P. cetrarioides Nyl. Flora, 1869, p. 290. Thallus large, 

 orbicular or expanded, subcoriaceous, smoothish, roundly lobed, 

 glaucous-white ; beneath brownish-black or blackish, paler at the 

 circumference, with few and short rhizinae ; lobes broad, crenate, 

 elevated, crisp and sorediate at the margins ( K + oran g e -y ellow , CaCT, 

 medulla K(CaCl)f+ reddish). Apothecia moderate or large, badio- 

 reddish, the margin entire ; spores 0,012-14 mm. long, 0,006-7 mm. 

 thick. Cromb. Lich. 13rit. p. 34 ; Leight. Lich. Fl. p. 128, ed. 3, 

 p. 119. Parmelia perlatci var. cetrarioides Del. in Dub. Bot. Gall. 

 (18^9) p. 6ul. 



Near to P. olivetorum, but usually (at least with us) a larger plant, and 

 with a different medullary reaction with CaCl. It also resembles states 

 of Ptatysma glaucum, from which the sparingly rlminose under surface 

 separates it. In some habitats, as also in herbaria, the thallus becomes 

 brownish and the sorediaform a tine narrow border on the margins of the 

 lobes. The apothecia in this country are extremely rare, and only once 

 seen fully developed. The speruiogoues also are seldom present. 



Hub. On the trunks of old trees, rarely on rocks, in wooded maritime 

 aud upland districts. Distr. Rather local and scarce in N. Wales, 

 8. Scotland, and the W. Highlands; rare in the Channel Islands. 

 B. M. : Rozel, Island of Jersey. New Forest, Hampshire ; Isle of 

 Wight ; Dartmoor and Bickleigh Vale^ Devonshire ; Helminton, Corn- 

 wall ; Dolgelly, Aberdovey, and near Barmouth (fruit), Merionethshire ; 

 Island of Auglesea. New Galloway, Kirkcudbrightshire ; Appin, Argyle- 

 shire ; Loch Katrine, Perthshire ; Loch Linnhe, Inverness-shire. 



4. P. perforata, Ach. Meth. (1803) p. 217. Thallus suborbicular, 

 membranaceous, imbricato-lobed or lobato-laciniate, smooth, mi- 

 nutely reticulato-rimulose, whitish or glaucous-white, beneath 

 brownish-black or black, with black dense rhizinae ; lobes crenato- 

 sinuate or siuuato-divided, often white-sorediate and occasionally 



eiliate at the margins (K+; en rusty ^ CaClI). Apothecia 

 moderate, perforate in the centre, badio-reddish or brownish-red, the 

 margin entire; spores 0,011-18 mm. long, 0,007-11 mm. thick. 

 Sm. Eng. Fl. v. p. 204 pro parte ; Cromb. Lich. Brit. p. 32 ; Leight. 

 Lich. Fl. p. 134, ed. 3, p. 123. Lichen perforates, "VVulf. in Jacq. 

 Coll. i. (1786) p. 116, t. 3 ; Eng. Bot. t. 2423 (mid. fig.). Parmelia 

 n-ticulata, Tayl. in Mack, Fl. Hib. ii. p. 148. Parmelia perlata, 

 /3. ciliata, Mudd, Man. p. 92 pro parte. Liclienoides glaucum, foli- 

 orum laciniis crinitis, Dill. Muse. 149, t. 20. f. 42 A. Brit.Kvs.: 

 Cromb. n. i.9 ; Larb. Lich. Hb. n. 250. 



Closely allied to P. perlata, but with the appearance of P. ciliata, 

 which, as already intimated, has been frequently confounded with it by 



