THELOTREMA. | LECANO-LECIDEET. 515 
disc dilated, the thalline margin tumid, rugose—Cromb. Grevillea, 
xix. p. 60. 
A good variety apparently constant to the characters given. The 
apothecia are often here and there ageregate in small protuberant 
groups. 
Hab, On trunks of old trees in wooded maritime and mountainous 
tracts.—Dustr. Only a few localities in S. and N. England, N. Wales, 
the S.W. Highlands of Scotland, and S. Ireland.—B. M.: New Forest, 
Hants; Nannau, Dolgelly, Merionethshire; Wark, Northumberland. 
Loch Creran, Argyleshire. Glenstale, co. Tipperary; Derricuintry, Kil- 
larney, co. Kerry. 
Form rupestre Cromb. Lich. Brit. (1878) p. 61.—Thallus mgre 
or less scattered, occasionally evanescent, otherwise as in the 
variety.—Leight. Lich. Fl. p. 248, ed. 3, p. 238.—Var. rupestre 
Turn. & Borr. Lich. Br. (1839) p. 180; Leight. Angio. Lich. p. 32, 
t. 12. £2; Mudd, Man. p. 278. Var. scutelliforme Tayl. in Mack. 
Fl. Hib. ii. p. 103. 
A depauperate state rather than a distinct form, resulting no doubt 
from the habitat. The thallus is at times subochraceous as noted by 
Leighton, who, however, erroneously says that the spores are 1—-2nee. 
Hab. On rocks in maritime and upland situations.—Distr. Sparingly 
in N. Wales, N. England, the 8.W. Highlands of Scotland, and W. 
Treland.—B. M.: Llyn Bodlyn and Cammlan Valley, Merionethshire ; 
Teesdale, Durham. Island of Lismore, Argyleshire. Kenmare Road, 
Killarney, co. Kerry ; Kylemore and Doughruagh Mts., Connemara, co. 
Galway. : 
2. T. subtile Tuck. Americ. Journ. Se. & Art, t. xxv. (1858) 
p. 426; Nyl. Flora, 1864, p. 491.—Thallus macular, somewhat 
shining, cream-coloured or whitish (K+ yellowish, CaCl—). Apo- 
thecia erumpent, small, colourless, the thalline margin slightly 
prominent, the proper margin often white-pulverulent ; spores 8ne, 
oblong, 10-13-locular, colourless, 0,040-56 mm. long, 0,009-0,010 
mm. thick.—Carroil, Journ. Bot. 1865, p. 289; Cromb. Lich. Brit. 
p. 61; Leight. Lich. Fl. p. 248, ed. 3, p. 239.—Brit. Exs.: Cromb. 
n. 169; Larbal. Lich. Herb. n. 62. 
An interesting plant, elsewhere found only in the United States of 
America. At first sight it looks as if it were only T. lepadinum with 
filmy thallus and smaller apothecia; but its real affinity is with 7. bi- 
cinctulum Nyl., an Australasian species, from which it differs chiefly in 
the larger spores. 
Hab. On smooth bark of trees in shady upland situations.—Dvstr. 
Only sparingly in W. Iveland.—B. M.: Turk Mt., Cromaglown, Kil- 
larney, and Lough Inchiquin, co. Kerry ; Lough Derryclare and Holly 
Island, Lough Inagh, Connemara, co. Galway. 
66. URCEOLARIA Ach. Prodr. (1798) p. 30 (ut tribus); Meth. 
p. 141 (ut genus) pro parte; Nyl. Mém. Soc. Cherb. iii. (1855) 
p- 180.—Thallus crustaceous, continuous or areolate, very rarely 
obsolete ; hypothallus white. Apothecia urceolato-impressed, with 
a proper and a thalline margin; hypothecium brown or blackish ; 
