214 LICHENACEI. [ALECXOKIA. 



7. A. tricolor Nyl. Mein. Soc. Cherb. v. (1857) p. 98. Thallus 

 filiform, erect, very much and divaricately branched, densely intri- 

 cate, black or brownish-black ; branches short, slender, rounded, 

 patent, subfibrillose, the apices usually somewhat curved and pale- 

 brown (K""" Cad ). Apothecia lateral, small, blackish; spores 

 shortly ellipsoid, 0,007-8 mm. long, 0,005-6 mm. thick. Mudd, 

 Man. p. 70 ; Cromb. Lich. Brit. p. 23; Leight. Lich. Fl. p. 86, ed. 3, 

 p. 78. Corniculctria bicolor Gray, Nat. Arr. i. p. 405 ; Hook. Fl. 

 Scot. ii. p. 69 ; Sm. Eng. Fl. v. p. 229. Lichen bicolor Ehrh. Beytr. 

 iii. (1789) p. 82 ; Eng. Bot. t. 1853. Lichen lanatus Huds. *F1. 

 Angl. p. 461 ; Lightf. Fl. Scot. ii. p. 892 ; With. Arr. ed. 3, iv. p. 57. 

 Usnea lance nigrce instar saxis adhcerens Dill. Muse. 66, t. 13. f. 8. 

 Muscus coralloides lance nigrce instar, saocis adhcerens Dill, in Kay, 

 Syn. ed. 3, p. 65, n. 3. Brit. Exs. : Mudd, n. 39 ; Cromb. n. 127". 



Though allied to A.jttbata, of -which it has been regarded as a variety, 

 yet, in the absence of any intermediate states, this is a very distinct 

 species. The apices of the thallus, which is at length free, are frequently 

 concolorous with the branches (var. melane.ira Ach. Lich. Univ. p. 614) ; 

 but this evidently results from exposure. The apothecia have been 

 gathered only in the Himalaya Mts. The spermogones are very minute, 

 more frequent towards the apices, with spermatia ; 008 mm. long, about 

 0,0005 mm. thick. 



Hob. On rocks and boulders among mosses in upland and subalpine 

 tracts. Distr. Frequent and sometimes abundant in mountainous tracts 

 of W. and N. England, N. Wales, and the Highlands of Scotland, but 

 apparently very rare in N.E. Ireland. B. M. : Hay Tor and Lustleigh 

 Cleeve, Dartmoor, Walkington, Devonshire ; Helminton, Cornwall ; Capel 

 Arthog, Llyn Bodlyn, and Cader Idris, Merionethshire; Island of Angle- 

 sea ; Farndale, Yorkshire ; Teesdale, Durham ; Kentmere, Westmore- 

 land. New Galloway, Kirkcudbrightshire ; Ben-A'an, near Taymouth, 

 Ben Lawers, Ben More, Glen Lyon, Corrie Uachlar, Rannoch, and Ben- 

 y-Gloe, Perthshire ; Canlochan, Forfarshire ; Lochnagar, Aberdeenshire ; 

 Ben Luighal, Sutherlandshire. Co. Antrim. 



Tribe XII. CETRARIEI Nyl. Mem. Soc. Cherb. iii. 

 (1855) p. 172; Syn. i. p. 297. 



Thallus subfruticulose or foliaceous, compressed or rarely rounded, 

 erect, ascending, or appressed, occasionally sparingly rhizinose be- 

 neath, internally filled with a white woolly medulla. Apothecia 

 lecanorine, marginal, obliquely affixed to the Iacinia3 ; spores 8na3, 

 small, simple, colourless ; paraphyses not discrete. Spermogones 

 enclosed in setuliform apiculi or black papilla ; sterigmata subsimple 

 or pauci-articulate. 



In habit and general appearance this tribe approaches some of the 

 Alectoriei, though in more important respects it is allied to the Par- 

 meliei. Having regard, however, to the usually fruticulose thallus, 

 the situation of the apothecia, and the character of the spermogones, 

 it is entitled to be separated from both. Most of the European species are 

 found in Britain. 



