7. A. bicolor Nyl. Mem. Soc. Cberb. v. (1857) ji. 98.—Thallus
filiform, erect, very mucli and divaricately branched, densely in tr icate,
black or brownisb-black ; branches short, slender, rounded,
p a tent, suhflbrillose, tb e apices usually somewhat curved and pale-
brown (K ~ , CaC13). Apotheoia late ra l, small, blackish; spores
shortly ellipsoid, 0 ,0 0 7 -8 mm. long, 0 ,0 0 5 -6 mm. thick.— Mudd,
Man. p. 70 ; Cromb. Lioh. B rit, p. 23 ; Leight. Lioh. Fl. p. 86, ed. 3,
p. 7 8 .— Cornicularia bicolor Gray, Nat. Arr. i. p. 405 ; Hook. Fl.
Scot. ii. p. 69 ; Sm. Eng. F l. v. p. 229. Lichen bicolor Eh rh . Beytr.
iii. (1789) p. 82 ; Eug. Bot. t. 1853. Lichen lanatus Huds. Fl.
Angl. p. 461 ; Lightf. F l. Scot. ii. p. 8 9 2 ; AVitli. Arr. ed. 3, iv. p. 57.
Usnea lance nigrce instar saxis adhcerens Dill. Muse. 66, t. 13. f. 8.
Muscus coralloides lance nigrce instar, saxis aclhcerens Dill, in Eay,
Syn. ed. 3, p. 65, n. 3.—B r it. E x s . : Mudd, n. 39 ; Cromb. n. 127.
Though allied to A . jubata, of v Inch it has been regarded as a variety,
yet, iu the absence of any intermediate states, tliis is a very distinct
species. The apices of the thallus, which is at length free, are frequently
concolorous with the branches (var. melaneira Ach. Lich. Univ. p. 614);
but this evidently results from exposure. The apothecia have been
gathered only in the Himalaya Alts. The spermogones are very minute,
more frequent towards the apices, with spermatia 0,008 mm. long, about
0,0005 mm. thick.
Hah. On rocks and boulders among mosses in upland and suhalpine
tracts.—Histr. Frequent and sometimes abundant in mountainous tracts
of AA'. aud N. England, N. AA’ales, and the Highlands of Scotland, but
apparently very rare iu N.E. Ireland.—B. AI. : Hay Tor and Lustleigh
Cleeve, Dartmoor, AA’alldngton, Devonshire; Helminton, Cornwall; Capel
Arthog, Llyn Bodlyn, and Cader Idris, Alerionethshire; Island of Anglesea;
Farndale, Yorkshire; Teesdale, Durham; Kentmere, AA’estmoreland.
New Galloway, Kirkcudbrightshire; Ben-A’an, near Tavmouth,
Ben Lawers, Ben Alore, Glen Lyon, Corrie Uachlar, Rannoch, and Ben-
y-Gloe, Perthshire ; Canlochau, Forfarshire; Lochnagar-, Aberdeenshire ;
Ben Luighal, Sutherlandshire. Co. Antrim.
Tribe X I I . CETEAEIEI Nyl. Mém. Soo. Cherb. iii.
(1855) p. 1 7 2 ; Syn. i. p. 297.
Thallus subfruticulose or foliaceous, compressed or rarely rounded,
erect, ascending, or appressed, occasionally sparingly rhizinose beneath,
inte rn ally filled w ith a white woolly medulla. Apothecia
leoanorine, marginal, obliquely affixed to th e laciniæ ; spores 8næ,
small, simple, colourless ; parajrhyses n o t discrete. Spermogones
enclosed in setuliform apiouli or black papiUæ ; 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 he separated from both. Alost of the European species are’
found in Britain.
39. CETRARIA Aoh. Aleth. (1803) p. 292 pro p a rte ; Nyl. Syn.
i. p. 298.—Thallus frutioulose, erect or ascending, more or less rigid,
laciniose, rarely fistulöse, eoncolo-
rous on both sides ; ejiithallus
somewhat shining ; medullary
y
lay e r with th e filaments loosely
interwoven, or in th e fistulöse
species arachnoid, scanty, in tr icate
Fig. 42.
Cetraria Islándica Ach.—a. A theca,
X350. b. Sjiores, X .5 0 0 . c. A’er-
tical section of a spermogone, x30.
d. Sterigmata and spermatia, X 500.
within ; cortical lay e r in te rnally
formed of longitudinal tubes,
externally cellular. Apothecia-
subooncolorous with th e thallus,
marginal, adnate on th e front of
th e apices of th e laciniæ, usually
w ith entire, sometimes w ith crenu
late margin ; hypothecium
colourless ; spores subellipsoid ;
hymenial gelatine bluish w ith iodine. Spermogones marginal,
spinuliform ; sterigmata simple ; spermatia cylindrical, moderate or
somewhat short.
This genus is especially characteristic of sub-arctic or alt-alpiue regions.
The thallus, which is of a lighter or darker spadiceous colour, becomes at
length free from the substratum. In most species the apothecia are very
rare or unknown in this country, and even the spermogones, which are
more frequent than the apothecia, are seldom seen in herbaria specimens,
in consequence of the spinules in which they are enclosed beiug
abraded.
I . C. Is lá n d ic a Ach. Meth. (1803) p. 293.—Thallus subfoliaceous,
cæspitose, variously laciniate, subcanaliculate, more or less ciliato-
spinulose a t th e margins, shining, pale-ohestnut-coloured or dark-
chestnufc-hrown, usually w ith impressed white soredia a t th e back,
often stained of a blood-red colour a t th e base (K _ , CaCl_).
Apotheoia adnate on th e upper surface of th e apices of the laciniæ,
larg e or moderate ; the m argin th in , entire or crenulate, a t length
ex cluded; spores 0,0 0 7 -1 1 mm. long, 0 ,0 0 4 -6 mm. th ick .—Gray,
Na t. A rr. i. p. 433 ; Hook. F l. Scot. ii. p. 51 ; Sm. Eng. El. v.
p. 221 ; Tayl. in Mack. El. Hib. ii. p. 155 ; Cromb. Lich. Brit. p. 25 ;
Leight. Liob. Fl. p. 96, ed. 3, p. 91.— Cornicularia Islándica, Mudd,
Man. p. 77, t. 1. f. 19. Lichen Islandicus Linn. Sp. PI. (1753)
p. 1145 a ; Huds. Fl. Angl. p. 448 ; Lightf. F l. Soot. ii. p. 829 ; Eng.
Bot. t. 1330 ; AVith. Arr. ed. 3, iv. p. 54. Lichenoides rigidum
eryngii fo liis referons Dill. Muse. 209, t. 28. f. I l l A , in Ray, Syn.
ed. 3, p. 77, n. 90.— B r it. E xs. : Mudd, n. 51 ; Leight. n. 42 pro
parte.
The thallus o fth e “ Iceland AIoss ” varies considerably in colour, being
sometimes almost entirely greyish-white, and in the character of the
laciniæ. The fertile laciniæ are broader at the apices than the barren.
The apothecia, which are seldom met with in this country, are usually of
moderate size, and become at length somewhat deformed. The spernio