PARMELIA | PARMELIACEE 147 
blackish, rhizinose to the margin (K=, CaCl rea). |§Apothecia 
small or moderate in size, scattered, rather dark-coloured, with a 
thickish, slightly crenulate margin; spores 9-12 y» long, 5-6 p 
thick.—Cromb. Lich. Brit. p. 36; Leight. Lich. Fl. p. 134; 
ed. 3, p. 123. PP. olivacea Fr. in Duby Bot. Gall. p. 602 (1830) ; 
f. furfuracea Scher. Enum. Lich. p. 47 (1850); var. furfuracea 
Mudd Man. p. 100 (1861). Lichenoides olivaceum, scutellis 
levibus Dill. Hist. Muse. p. 182, fig. 77, B (1741). 
Exsicc. Croall n. 591; Johns. n, 122. 
Characterized among brown Parmelix by the chemical reaction 
and by the dense covering of almost black isidia, sometimes only 
isolated lobes being visible. The apothecia and spermogones are 
rare, especially on saxicolous specimens. 
Hab. Chiefly on rocks and stones, also on old palings and on 
trees, in maritime and upland districts.—Distr. General though not 
common throughout the British Isles—B. M. La Moye, Jersey ; 
Penzance and near St. Breock, Cornwall; Runnymead, Surrey; North 
Hill and Herefordshire Beacon, Malvern, Worcestershire ; Haughmond 
Hill and Stiperstones, Shropshire; Hafod-Morfa and Borthwynog 
near Dolgelly and Rhew-greidden, Merioneth ; Trefriw and Bettws-y- 
Coed, Carnarvonshire ; near Ayton, Cleveland, Yorkshire; near Ken- 
dal, Westmoreland, Cumberland ; New Galloway, Kircudbrightshire ; 
Head of Loch Awe, Argyll; Glen Lochay, Falls of Tummel and Blair 
Athole, Perthshire; Glen Shee, Forfarshire; Portlethen and Durris, 
Kincardineshire ; Hill of Ardo and Castleton of Braemar, Aberdeen- 
shire; S. of Fort William, Invernessshire ; near Abernethy, Elgin ; 
Dawros River, near Kylemore, Connemara, Galway; Clare Island and 
Achill Island, Mayo. 
Var. letevirens Nyl. in Bull. Soc. Linn. Norm. sér. 2, vi. 
p- 272 (1872).—Thallus orbicular or spreading, lobes large and 
colour lighter than in the species, with generally fewer, lighter- 
coloured isidia (medulla CaCl + red, fugitive). Apothecia similar 
to the species.—Cromb. in Grevillea x. p. 26 (1881). Form 
olivacea Leight. Lich. Fl. ed. 3, p. 123 (1879). BP. Borreri 
f. olivacea Leight. Lich. Fl. ed. 2, p. 479 (1871). Imbricaria 
olivacea var. letevirens Flot. in Uebers. Schles. Ges. Breslau, 
1850, p. 131 (1851). 
Exsicc. Bohl. n. 86; Johns. nos. 248, 249. 
Though lighter in colour and largely different in habitat there are 
transition forms between this and the species. In some species the 
isidia are crowded and dark coloured, in others they are very sparingly 
formed (f. denwdata Cromb. in Grevillea x. p. 71 (1887)). Frequently 
the isidia are abraded, giving the thallus a white-punctate appearance. 
Hab. On old trees and palings, rarely on walls in maritime and 
upland districts.—-Disty. Not uncommon throughout Great Britain 
and Ireland.—B. M. Ardingly, Sussex; North Hill, Malvern, Worces- 
tershire; Devil's Bridge, Cardiganshire; near Dolgelly and Rhew- 
greidden, Merioneth ; Capel Curig and Bettws-y-Coed, Carnarvon- 
shire ; Hopton, Suffolk; near Guisboro, Cleveland, Yorkshire ; Kendal 
and Leven’s Park, Westmoreland; Keswick, Cumberland; Appin 
and head of Loch Awe, Argyll; Craig Calliach, Loch Ard and Glen 
i 2 
