Ilab. On the smooth bark of a young tree in a maritime district.—
Distr. Extremely local and rare, in S. England.—B. AI. : Near R} de,
Isle of Wight.
18. P. e ro sa Leight. Lioh. Fl. (1871) p. 152.— Thallus suborbicular,
moderate, shortly laciniate, greyish or glauoous-whito;
beneath u bitish, spariugly fibrilloso-rhizinose ; laciniæ crowdedly
imbricate, more or less ascending, rounded and oroso-lacerate or a t
length pulverulent at th e apices (K+yellow, CaCl+yellow). Apothecia
moderate, brownish-black, the thalline margin suhentire ;
sporos oblong, 0 ,0 1 4 -2 0 mm. loug, 0 ,0 0 7 -1 0 mm. th io k .-C rom b .
Journ. Bot. 1872, p. 358 ; Leight. Lich. Fl. ed. 3, p. 139. Par-
nielia erosa Borr. Eng. Bot. Suppl. 1837, t. 2807. Borrera cæsia
y. albinea (non Ach.) Aludd, Alan. p. 108, t. ii. f. 31 ; Cromb.
Lich. Brit. p. 39. Squamaria tribacia Sm. Eng. El. ii. p. 194 pro
pm tc .— Brit. Exs. : Leight. n. 2(50; Larb. Cæsar. n. 2 4 ; Lioh. Ilb .
n. 294.
A well-marked species somewhat resembling P. tribacia, from w l^ h
it is well distinguished by the efarinose and esorediate thallus, the apices
of the laciniæ, and tlie different chemical reactions. The apothecia,
which with us are extremely rare, are chiefly central, numerous, with the
thalline margin at length suborenate.
Hah. On trees, walls, and rocks in maritime and upland districts.—
Distr. Not very general nor common throughout England and in the
Chanuel Islands ; rare in S. Scotlaud, the S.AV. Highlands and S. Grampians
; not yet seen in Ireland.—B. AI. : Rozel, St. Ouen’s, and La Aloye,
Island of Jersey ; Jerbourg and Aloulin Huet, Island of Guernsey. Bexhill
and Hurstpierpoint, Sussex ; Porchester, Hants ; Plymouth and
AVembury, S. Devon; near Penzance and AVithiel, Cornwall ; St. Alary’s,
Scilly ; near Swindon, W ilts ; Alalvern, Worcestershire ; Nannau, Dolgelly,
Barmouth, and Aberdovey, Alerionethshire; near Ayton, Cleveland,
Yorkshire ; near Staveley, AVestmoreland. New Galloway, Kirkcudbrightshire
; Barcaldine, Argyleshire ; Ben Lawers, Perthshire.
19. P. a s tro id e a Nyl. Act. Soo. Linn. Bord. sor. 3, i. (1850)
p. 308.—ThaUus orbicular, thin, closely adpressed, granulose or
leprose in th e centre, laciniato-effigurate a t th e circumference,
greyish-white ; beueath whitish, black fibrilloso-rhizinose ; laciniæ
narrow, contiguous (K ^ y e llow , CaCl+ycUow). Apothecia innato-
sessile, small, concave or plane, brownish-blackish, naked or prui-
noso, the th allin e margin inflexed, crenulate ; spores ellipsoideo-
oblong, 0,0 1 7 -2 6 mm. long, 0 ,0 0 8 -1 1 mm. thick.— Cromb. Lich.
Brit. p. 39 ; Leight. Lich. Fl. p. 153, ed. 3, p. 139.— Borrera
astroidea et p . Clementi Aludd, Alan. p. 108, t. ii. f. 32. Parmelia
astroidea Clem. E ns. Add. (1807) p. 302. Squamaria Clementi
Sm. Eng. El. v. p. 196. Parmelia Clementi Turn. Trans. Linn. Soo.
ix . p. 146, t. 13. f. 1 ; Gray, Nat. Arr. i. p. 439 ; Tayl. in Mack.
El. Hib. ii. p. 147. Lichen Clementi Eng. Bot. t. 1779.— Parmelia
columnaris Tayl. in Fl. Hib. ii. p. 144, is a more granulose state.—•
B rit. Exs. : Leiglit. n. 324.
Easily recognized by the thallus being often almost entirely granulose
or leprose, with the laciniæ visible only at or towards the circumference.
With us it is but seldom and sparingly seen with apothecia. The spermogones
apparently do not occur in Britain.
Hab. On the trunks of trees, often in orchards, and ou tiled roofs in
maritime and lowland districts.—Distr. Somewhat local and scarce iu
S. and Central England, N. AA’ales, S. Ireland, aud the Channel Islands ;
not seen from Scotland.—B. AI. : St. Alartiu’s, Island of Jersey ; Island of
Guernsey. Epping Forest, Essex; near Alaidstone and Tuiihridgo AA’ells,
Kent ; near Lewes, between Henfield and Briglitou, aud Hurstpierpoint,
Sussex; near Southampton, H ants ; Ryde, Isle of AVight; near riyinouth,
Devonshire ; Penzance, Oornwall ; West Haddon, Nonhamptonshire ;
near Barmouth, Alerionethshire. Tervoe, oo. Limerick ; Carrigalim, uear
Cork.
Form elegans Nyl. ex Leight. Lich. F l. ed. 3 (1879) p. 139.—
Thallus glaucous-white ; laciniæ finely isidioso-fimbriate a t th e m argins.
Apotheoia n o t seen.—B r it. Exs. ; Larb. Lioh. Hb. n. 88.
The peculiar fimbriate margins of the laciniæ, which are not leproso-
granulose, render this a somewhat distinct form. I t does not occur
fertile.
Hab. On rocks in a maritime district.—Distr. Found only very
spariugly in N.W. Ireland.—B. AI. : Kylemore Lake, co. Galway.
20. P. cæsia Njd. Act. Soo. Linn. Bord. sér. 3, i. (1850) p. 308.
—ThaUus orbicular, closely adnate, stellate, multifido-laoiniate,
ooesio-white or greyish-white, sprinkled w ith cæsious subglobose
soredia ; beneath pale and sparingly fibrillose ; laoiniæ narrow, convex,
contiguous, slightly dilated a t th e apices (K]|]yoUow, C aC l/).
Apotheoia sessile, small, concave or plane, black, naked or pruinose,
th e thalline margin thiokish, entire or c ren u late ; spores oblong,
0 ,0 1 6 -2 3 inm. long, 0 ,0 0 9 -1 3 mm. thick.—Cromb. Lich. Brit. p. 39.
— Physcia stellaris var. ccmia Leight. Lioh. F l. p. 152, ed. 3, p. 141.
Borrera cæsia Mudd, Alan. p. 107. Squamaria cæsia Sm. Eng. Fl.
V. p. 196. Parmelia cæsia Gray, Nat. Arr. i. p. 443 ; Tayl. in Alack.
El. Hib. ii. p. 147. Lichen cæsius Hoffm. Enum. (1784) p. 65,
t. 12. f. 1 ; Eng. Bot. t. 1052. Liehen Psora Dicks. Crypt, faso. iii.
p. 17 ; With. Arr. ed. 3, iv. p. 26. Lichenoides cinereum, segmentis
argutis stellatis, seutellis nigris Dill. AIuso. 176, t. 24. f. 70 o.— Brit.
E xs. : Leight. n. 323.
Distinguished from its more immediate allies by the pulvinate cæsious
soredia, which are scattered regularly over the thallus and rarely become
confluent. The apothecia are chiefiy'central and not of frequent occurrence.
Hab. On walls, roofs, and boulders iu lowland and upland districts.—
Distr. General though uot common in Englaud ; much rarer in Scot