G8 COLLEMACEI. [lEPTOGICM. 



sometimes also ou the ti-uuks of old trees (willow and ash) in maritime 

 and upland districts. — Distr. Local, though common where it occurs, in 

 the Channel Islands, S. and W. England, and S.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 Xyl. Flora, 1865, p. 210.— Thallus small, 

 somewhat firm, adnata, granulate or granulato-areolate, placodioideo- 

 radiate at the circumference, olive or dark-olive, the radii and gra- 

 niJea convex. Apothecia not seen rightly developed. — Cromb. 

 Journ. Bot. 1882, p. 272. — Leptoriium 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 CoUemoduim fragile, but it is readily 

 distinguished from this and allied species by its placodioid appearance. 

 In one British specimen young apothecia are sparingly present. 



Hah. On calcareous rocks in upland hilly districts. — Disfr. Extremely 

 local and scarce, in W. England. — B. M. : Cleeve Ilill, Somersetshire. 



11. L. muscicola Fr. Sum. Veg. (1846) p. 122. — ThaUus pulvi- 

 nate. filamentoso-fruriculose. 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), oblougo-fusiform, 0,023- 

 27 mm. long, 0,007 ram. thick.— -Xyl. Syn. i. p. 134, t. iv. ff. 11- 

 15 : Cromb. Lich. Brit. p. 10 ; Leight. Lich. Fl. p. 27, ed. 3, p. 34. 

 — PohjcMd'tum muscicola Gray, Xat. Arr. i. p. 402 ; Mudd, Man. 

 p. 49, t. i. f. 9. ColUma muscicola Hook. Fl. Scot. ii. p. 72 ; Sm. 

 Eng. Fl. V. p. 214; Tayl. in Mack. Fl. Hib. ii. p. 111. Lichen 

 muscicola Sw. X. Act. Ups. iv. (1784) p. 248 ; Dicks. Crvpt. fasc. ii. 

 t. 6. f. 9 ; With. Arr. ed. 3, iv. p. 46 ; Engl. Bot. t. 2264.— Bnt. 

 Exs. : Leight. n. 395 ; Larb. Lich. Hb. n. 122. 



This plant is unlike any of the CoUemei, resembling when dry and sterile 

 some young and paler state oi Parnielia lanata. The thallus is composed 

 of somewhat large elongate cells, which become smaller and subaugular 

 at the surface, the gonimic gramdes, which are scanty, being here and 

 there aggregate in the cells. The brandies, which are rigid when di-y, 

 are numerous and intricate, the lower ones sometimes anastomosing. 

 The apothecia are horizontal, very much broader than the bi'anches, 

 while occasionally one is common to two or three of the branches. 



Hah. Among mosses on rocks and walls, in maritime, upland, and 

 subalpine districts. — Distr. General and not uncommon in mountainous 

 rpgions, chiefly of W. Britain, rare in the Channel Islands, and in E. and 

 W. Ireland. — B. M. : Quenvais, Island of Jersey. South Brent, Bottor 

 Rock, and near Hunter Tor, Devonshire : Ciider Idris. Drews-y-nant and 

 Ty Gwyn, near Dolgelly, Merionethshire ; Llanberis Pass andSnowdon, 



