CETRAKIA.] CETRARTF.I. 217 



Hab. On the ground among mosses in subalpine and alpine districts. 

 Distr. Local in N. Wales, N. England, and S. Scotland, more frequent 

 among the Grampians, especially in Braemar. B. M. : Snowdon and 

 Carnedd Llewellyn, Carnarvonshire ; Teesdale, Durham. Pentland Hills, 

 near Edinburgh ; Mael Graedha, Ben Lawers, and Eannoch, Perthshire ; 

 Katelaw, Forfarshire : Morrone and Ben-naboord, Braemar, Aberdeen- 

 shire ; Ben Nevis, Inverness-shire. 



Form subtubulosa Cromb. Grevillea, xv. (1886) p. 48. Laciniae 

 interruptedly tubulose, with the suture ciliato-spinulose. Apothecia 

 not seen. Cetraria Islandicaf. subtubulosa Fr. Lich. Eur. (1831) 

 p. 37. 



A modification of the preceding, which scarcely deserves to rank as a 

 separate form. The thallus is only sparingly branched, and is never seen 

 fertile. 



Hab. On mossy ground among boulders in alpine places. Distr. Local 

 and uncommon on a few of the higher Grampians, Scotland. B. M. : Kate- 

 law, Forfarshire ; Ben-naboord and Cairntoul, Braemar, Aberdeenshire. 



3. C.biascens Fr. fil. Lich. Scand. (1871) p. 98. Thallus densely 

 caespitose, subfoliaceous, canaliculate or somewhat plane, opaque, pale- 

 or dark-brown, with white impressed soredia at the back, often stained 

 yellowish-brown at the base ; lacinise narrow, sparingly ciliato-spinu- 

 lose, much and repeatedly dichotomously branched at the apices (K~ 

 CaClj." ^^k). Apothecia adnate to the upper surface of the apices 

 of the laciniae, elevated, moderate, subconcolorous, the margin some- 

 times denticulate ; spores as in the preceding species. Croinb. 

 Grevillea, xv. p. 48. Cetraria aculeata b. Jdascens Fr. Lich. Europ. 

 (1831) p. 36. Cetraria Delisei (Bory), Cromb. Lich. Brit. p. 26 ; 

 Leight. Lich. Fl. p. 97, ed. 3, p. 92. 



Differs from C. crispa in the lacinia? and the chemical reaction of the 

 medulla. The thallus, which is rather brittle when dry, varies consider- 

 ably in colour and in the length of the lacinise, being dark and short in 

 Britain. Neither the apothecia nor the spermogones occur in this 

 country. 



Hub. Among mosses on the ground in alpine places. Di-ttr. Ex- 

 tremely local and rare on the summits of two of the loftier N. Grampians, 

 Scotland. B. M. : Lochnagar and Ben Macdhui, Braemar, x\berdeenshire. 



4. C. aculeata Fr. Syst. Orb. Yeg. (1825) p. 239. Thallus caespi- 

 toso-fruticulose, rigid and somewhat fragile, fistulose, erect, some- 

 what rounded or anguloso- unequal, or somewhat compressed, sub- 

 lacunose, very much and irregularly branched, bright- or dark- 

 brown; branches divaricate, more or less blackish -spin ulose (K~> 

 CaCl^)- Apothecia subterminal, concolorous, small or moderate, 

 the margin spinuloso-denticulate ; spores 0,005-9 mm. long, 0,003- 

 4 mm. thick. Cromb. Lich. Brit. p. 26 ; Leight. Lich. Fl. p. 97, 

 ed. 3, p. 92. Cornicularia aculeata Gray, Nat. Arr. i. p. 405 ; Hook. 

 Fl. Scot. ii. p. 69 ; Sm. Eng. Fl. v. p. 228 : Tayl. in Mack. Fl.Hib. 

 ii. p. 86 ; Mudd, Man. p. 77 (incl. (3. calocaula Flott.). Lichen acu- 



