PAEMELIA.] PABMELIE1. 255 



Var. /3. laetevirens Nyl. Bull. Soc. Linn. JSTormand. vi. 1872, 

 p. 272. Thallus orbicular or effuse, greenish-olive or greenish- 

 brown, more or less covered with concolorous isidia (medulla (/aCl + 

 red). Apothecia and spores as in the type. Cromb. Greviliea, x. 

 p. 26. Imbricaria olivacea y. Icetevirens Flot. Lich. Sil. (1829) 

 n. 90. Parmelia fuliyinosa f. olivacea Leight. Lich. Fl. ed. 3, p. 123. 

 Parmelia Borreri f. olivacea Leight. Lich. Fl. ed. 2, p. 479. 



Though differing in the colour of the thallus and of the isidia, the 

 reaction of the medulla shows that this is only a variety of P. fuliyinosa. 

 States occur in which there is scarcely auy trace of isidia (form denudata 

 Cromb., probably referable tosubsp. ylabratula Lamy, as in Greviliea, xv. 

 p. 75). In herbaria specimens the isidia often become abraded, rendering 

 the thallus white-punctate. The apothecia are not uncommon, but the 

 spermogones are rarely seen. 



Hob. On old trees and pales, rarely on Avails, in maritime and upland 

 districts. Distr. Local and scarce in E. and N. England, N. Wales, the 

 Highlands, Scotland, and N.W. Ireland. B. M. : Hopton, Suffolk; 

 Bettws-y-Coed, Denbighshire ; near Dolgelly and llhewgreidden, Merio- 

 nethshire ; Devil's Bridge, Cardiganshire ; Kendal and Levens Park, 

 Westmoreland ; Keswick, Cumberland. Appin and head of Loch Awee, 

 Argyleshire ; Loch Ard and Glen Lochay, Perthshire ; Durris, Kincar- 

 dineshire ; Morrone, Braemar, Aberdeenshire. Derryclare and near Kyle- 

 more, co. Galway. 



26. P. Stygia Ach. Meth. (1803) p. 203. Thallus orbicular, 

 appressed, somewhat shining, smooth, imbricate, olive-brown or 

 blackish ; beneath pitch-black, paler at the margins, with but few 

 rhizinse ; Iacinia3 sublinear, palmato-multifid, convex, incurved at the 

 apices (K~, CaCl 3)- Apothecia moderate or somewhat large, sub- 

 concolorous, the margin granulato-crenate ; spores 0,008-10 mm. 

 long, 0,006-7 mm. thick. Gray, Nat. Arr. i. p. 441 ; Hook. Fl. 

 Scot. ii. p. 54 ; Sm. Eng. Fl. v. p. 202 ; Mudd, Man. p. 100 ; Cromb. 

 Lich. Brit. p. 35 ; Leight. Lich. Fl. p. 124, ed. 3, p. 116. 

 Lichen sti/gius Linn. Sp. PI. (1753) p. 1143 ; Dicks. Crypt, fasc. iii. 

 p. 16 ; With. Arr. ed. 3, iv. p. 30 ; Eng. Bot. t. 2048. Brit. EMS. : 

 Dicks. Hort. Sic. n. 25 pro parte. 



Somewhat resembles Platysma Fahlunense, but distinguished by the 

 form of the lacinise, the character of the spermogones, and the absence of 

 medullary reaction with K. It is generally fertile, though the apothecia 

 are rather scattered and not numerous. The spermogones, which are 

 frequent, are immersed, with spermatia 0,005 mm. long, 0,001 mm. thick, 

 constricted in the middle and somewhat obtuse at the apices. 



Hub. On rocks and boulders, granitic and quartzose, in subalpine and 

 alpine regions. Distr. Local and rare, being confined to a few of the 

 higher Grampians, Scotland. B. M. : Ben More, Perthshire ; Lochnagar, 

 Ben-naboord and Ben Macdhui, Braemar, Aberdeenshire ; Ben Nevis, In- 

 verness-shire. 



27. P. alpicola Fr. fil. Nov. Ac. Reg. Soc. Sc. Cpsal. (1861) 

 p. 157. Thallus orbicular or expanded, somewhat appressed and 

 adnate, subopaque, blackish- olive or dark-grey; beneath very black, 



