68 COLLEMACEL. , [LEPToGIUM. 
sometimes also on the trunks of old trees (willow and ash) in maritime 
and upland districts Distr. Local, though common where it occurs, in 
the Channel Islands, 8. and W. England, and 8.W. Highlands, Scotland. 
—B. M.: Rozel and coast of the Island of Jersey. Shiere, Surrey (in 
fruit); near Maidstone, Kent; near Lewes, Sussex; Cheddar Cliffs, 
near Porloch and Yatton, Somersetshire; Weston-super-Mare (in fruit), 
Brinscomb, and near Cirencester, Gloucestershire; Malvern and Aston, 
Worcestershire ; Blaxton, Yorkshire; Eden, Westmoreland. Barcaldine, 
Argyleshire. 
10. L. placodiellum Nyl. Flora, 1865, p. 210.—Thallus small, 
somewhat firm, adnate, granulate or granulato-areolate, placodioideo- 
radiate at the circumference, olive or dark-olive, the radii and gra- 
nules convex. Apothecia not seen rightly developed—Cromb. 
Journ. Bot. 1882, p. 272.—Leptogium diffractum Kremp. Flora, 
1861, p. 258, is a prior name, but had previously been given to a 
species of Collema. 
This resembles a small condition of Collemodium fragile, but it is readily 
distinguished from this and allied species by its placodioid appearance. 
Jn one British specimen young apothecia are sparingly present. 
Hab. On calcareous rocks in upland hilly districts— Distr. Extremely 
local and scarce, in W. England.—B. M.: Cleeve Hill, Somersetshire. 
11. L. muscicola Fr. Sum. Veg. (1846) p. 122.—Thallus pulvi- 
nate, filamentoso-fruticulose, rounded or slightly compressed, dark- 
brown or olive-black; branches minute, cylindrical, suberect or 
decumbent, intricate, somewhat obtuse at the apices. Apothecia 
subterminal, moderate, appressed, brownish-red, the margin thin, 
entire, pale; spores 1-septate (bilocular), oblongo-fusiform, 0,023- 
27 mm. long, 0,007 mm. thick.—Nyl. Syn. i. p. 134, t. iv. ff. 11- 
15; Cromh. Lich. Brit. p. 10; Leight. Lich. Fl. p. 27, ed. 3, p. 34. 
—Polychidium muscicola Gray, Nat. Arr. i. p. 402; Mudd, Man. 
p. 49, t.i. f. 9. Collema muscicola Hook. Fl. Scot. ii. p. 72; Sm. 
Eng. Fl. v. p. 214; Tayl. in Mack. Fl. Hib. ii. p. 111. Lichen 
muscicola Sw. N. Act. Ups. iv. (1784) p. 248 ; Dicks. Crypt. fase. ii. 
t.6.f.9; With. Arr. ed. 3, iv. p. 46; Engl. Bot. t. 2264.—Brit. 
Exs.: Leight. n. 395 ; Larb. Lich. Hb. n. 122. 
This plant is unlike any of the Colleme?, resembling when dry and sterile 
some young and paler state of Parmelia lanata, The thallus is composed 
of somewhat large elongate cells, which become smaller and subangular 
at the surface, the gonimic granules, which are scanty, being here and 
there aggregate in the cells. The branches, which are rigid when dry, 
are numerous and intricate, the lower ones sometimes anastomosing. 
The apothecia are horizontal, very much broader than the branches, 
while occasionally one is common to two or three of the branches. 
Hab. Among mosses on rocks and walls, in maritime, upland, and 
subalpine districts. Distr. General and not uncommon in mountainous 
regions, chiefly of W. Britain, rare in the Channel Islands, and in E. and 
- Ireland.—B. M.: Quenvais, Island of Jersey. South Brent, Bottor 
Rock, and near Hunter Tor, Devonshire; Cader Idris, Drews-y-nant and 
Ty Gwyn, near Dolgelly, Merionethshire ; Llanberis Pass and Snowdon, 
