PERTUSARIA. | LECANO-LECIDEEL. 509 
27. P. gyrocheila Nyl. Flora, 1865, p. 354.—Thallus deter- 
Mminate, subgranuloso-unequal, rimoso-diffract, greyish (K + yellow, 
CaCl —).  Apothecia in thelotremoid tubercles, simple or at 
length subgyrose, the thalline margin thick, subgyrose ; epithecium 
glypholeceine, hymenium pale; spores 0,068-70 mm. long, 0,036— 
50 mm. thick; hymenial gelatine and the thece bluish with 
iodine.—Carroll, Journ. Bot. 1866, p.23; Cromb. Lich. Brit. p. 61; 
Leight. Lich. Fl. p. 241, ed. 3, p. 232. 
A very distinct species well characterized by the peculiar form ofthe 
fructification. The thallus is small, with the fertile verrucee more or less 
scattered and crateriform. The very few specimens gathered are only 
sparing fertile. 
Hab. On mica-schist rocks in an alpine situation.—Distr. Extremel 
local and scarce on one of the 8S. Grampians, Scotland.—B. M.: Summit 
of Ben Lawers, Perthshire. 
b. Spores normally 4ne. 
28. P. leioplaca Schaer. Spicil. (1823) p. 66; Nyl. Lich. Scand. 
p. 181.—Thallus subdeterminate, thin or rarely submoderate, 
smooth or ruguloso-unequal, rimose, milk-white, yellowish-white 
or whitish (K— or f+ yellowish). Apothecia in somewhat convex, 
smooth, usually discrete verruce, the ostioles solitary or few 
(1-3-5), punctiform, dark; spores usually 4nex (but variable in 
number), oblongo-ellipsoid or subellipsoid, 0,042-75 mm. long, 
0,020-838 mm. thick.—Mudd, Man. p. 267; Cromb. Lich. Brit. 
p. 60; Leight. Lich, Fl. p. 244, ed. 8, p. 234.—Porina leioplaca 
Ach. Vet. Ak. Handl. 1809, p. 159; Lich. Univ. p. 309, t. 7. f. 2. 
Pertusaria communis var. 6. leioplaca Turn. & Borr. Lich. Br. 
p. 197.—Brit. Eas. Leight. n. 230; Mudd, nos. 265, 267. 
The thallus varies somewhat in thickness, becoming at times subcon- 
crescent, when the verruce are more prominent. As noted by Th. M. 
Fries (Lich. Scand. p. 316), the chemical reaction varies according to the 
colour of the thallus, being little (or not) distinct when it is dealbate. 
The apothecia are also variable, usually solitary, rarely 3 or 5 in the 
verruce, with the spores at times 3-5-6-8ne, very rarely 2ne (ina 
single British specimen). ° 
Hab, On the trunks of trees in maritime and upland districts.— Distr. 
In most parts of Great Britain, no doubt also of Ireland; not seen from 
the Channel Islands.—B. M.: Near Highbeach, Epping Forest; Ightham, 
Kent; St. Leonard’s Forest, Sussex; Shanklin, Isle of Wight; New 
Forest, Hants; Lustleigh, 8. Devon; Withiel, Cornwall; near Ciren- 
cester, Gloucestershire; Woodbury Hill and Malvern, Worcestershire ; 
Gopsall Park, Leicestershire ; Gloddaeth, Carnarvonshire ; Bettws-y- 
coed, Denbighshire ; Island of Anglesea; Newton Wood and Sowerdale, 
Cleveland, Yorkshire; Lamplugh, Cumberland. Barcaldine, Argyle- 
shire ; Craig Calliach, Killin an Falls of Moness, Aberfeldy, Perthshire ; 
Moor of Morrone, Braemar, Aberdeenshire ; Glen Nevis, Inverness-shire, 
Enniskean, co. Cork; McCarthy’s Island and Upper Lake, Killarney, co, 
Kerry ; Renvyle Wood, Connemara, co. Galway, 
