PARMUELIA.] PARMELIEI. 233 
It may be divided into the following sections (or subgenera) and sub- 
sections, according to the presence or absence of rhizine and the colour of 
the thallus. 
A. RHIZINOSAi.—Thallus more or less distinctly fibrilloso- 
rhizinose beneath (subgenus Hyporhizia Cromb. Grevillea, xv. 
(1887) p. 74). 
a. Glaucescentes.—Thallus normally grey, greyish-white or 
glaucous. 
1. P. perlata Ach. Meth. (1803) p. 216.—Thallus orbicular or 
expanded, imbricato-lobed, smooth, glaucous- or greyish-white ; 
beneath somewhat shining, brownish-black or blackish, paler at the 
circumference, with short scattered rhizinee; lobes rounded, often 
white-sorediate towards the margins (Tralee, allow, CaCl—), 
Apothecia moderate or large, scattered, badio-reddish, the margin 
thin, entire; spores 0,011-17 mm. long, 0,007-12 mm. thick.— 
Gray, Nat. Arr. i. p. 437; Hook. Fl. Scot. ii. p. 52; Sm. Eng. FI. 
v. p. 200; Tayl. in Mack. Fl. Hib. ii. p. 148; Mudd, Man. p. 92; 
Cromb. Lich. Brit. p. 33; Leight. Lich. Fl. p. 128, ed. 3, p. 119. 
—Lichen perlatus Linn. Syst. Nat. ed. 12 (1767) p. 712; Huds. 
Fl. Angl. p. 448; Lightf. Fl. Scot. ii. p. 839; With. Arr. ed. 3, 
iv.p.68. Lichenoides glaucum perlutum, subtus nigrum et cirrhosum 
Dill. Muse. 147, t. 20. f. 39, a, 3, D, E— Brit. Hvs.: Leight. n. 76, 
392; Larb. Lich. Hb. n. 291. 
Several species were included under this which have been definitely 
separated by the chemical reactions of the medulla. P. perlata is now 
seen to be a much less variable plant than was supposed, though the 
thallus varies in the presence or absence of soredia. The apothecia are 
very rare in this country, por are the spermogones often seen. When 
present, they are scattered, minute, blackish, with spermatia about 
0,005-6 mm. long, scarcely 0,001 mm. thick. 
Hab. On the trunks of old trees and on rocks in maritime and upland 
tracts.—Distr. General and often plentiful in most parts of Great Britain 
and in the Channel Islands; apparently rare in Ireland.—B. M.: Islands 
of Jersey, Sark, and Guernsey. St. Leonard’s Forest, near Brighton, 
Hlenfield, and Arundel, Sussex ; Lyndhurst, New Forest, Hants; Isle of 
Wight; Torquay, South Brent, Hay Tor, Dartmoor, and Jfracombe, 
Devonshire; Bocconoc, near Penzance, and Withiel, Cornwall; near 
Cheltenham, Gloucestershire ; Twycross, Leicestershire ; Harboro’ Magna, 
Warwickshire; Wrighton Park, Herefordshire ; Haughmond Hill, Shrop- 
shire; Llanbedr, Barmouth, and Dolgelly, Merionethshire; Bousdale 
Gill, Cleveland, Yorkshire; Stavely, Kendal, and Windermere, West- 
moreland. New Galloway, Kirkcudbrightshire ; near Inverary and Bar- 
caldine, Argyleshire; Loch Katrine and Killin, Perthshire ; 8. of Fort 
William, Lochaber, Inverness-shire; Applecross, Ross-shire. Near 
Cork; Dunkerron, co. Kerry. 
Subsp. P. ciliata Nyl. Flora, 1878, p. 247.—Thallus moderate 
or large, imbricato-lobed, smoothish,' often isidiiferous, white or 
