LECANORA. | LECANO-LECIDEE1. 405 
0,009-12 mm. long, 0,005-7 mm. thick; paraphyses slender, dis- 
crete, not clavate at the apices; hymenial gelatine bluish, then 
sordid with iodine—Mudd, Man. p. 149; Cromb. Lich. Brit. p. 50; 
Leight. Lich. Fl. p.206, ed. 3, p. 189.—Parmelia galactina Ach. Meth. 
(1803) p. 190. Lichenoides crustosum, orbiculare, incanum Dill. 
Muse. p. 135, t. 18. f. 17 3.—Brit. Evs.: Mudd, n.116; Leight. n. 
400. 
A common plant overlooked by our older authors and rarely appearing 
in their herbaria s, u. Lichen muralis, along with L. saxicola, At first the 
thallus is orbicular, small, and squamarioid in appearance ; but it is often 
little developed, and frequently at length is indeterminate. The apothecia 
are numerous, crowded towards the centre, and thus often angulose. It 
is in other respects a rather variable plant, presenting the form and sub- 
species that follow. 
Hub. On walls and rocks, chiefly calcareous, from maritime to upland 
districts.— Distr. General and common in most parts of Great Britain ; 
rare in the Channel Islands and in SE, and N.W. Iveland.—B. M.: 
Island of Sark; Rozel, Jersey. Bury St. Edmund’s, Suffolk; Holloway, 
London; Stanmore, Middlesex ; Crystal Palace, Surrey; Peasemarsh and 
Hastings, Sussex ; Newlyn Cliff, Penzance and Withiel, Cornwall; Cleve 
Hill and Bathampton Downs, Somersetshire ; Charnwood Forest, Leices- 
tershire ; Great Malvern, Worcestershire; Shiffnal and Oswestry, Shrop- 
shire; Island of Anglesea; near Ayton, Cleveland, Yorkshire. King’s 
Park, Stirling; Ben Lawers and Craig Tulloch, Perthshire; Portlethen, 
Kincardineshire; Craig Guie, Braemar, Aberdeenshire; near Fort 
William, Inverness-shire. Near Cork; Kylemore Lake, Connemara, co. 
Galway. 
Form verrucosa Leight. Lich. Fl. ed. 3 (1879), p. 190.—Thallus 
pulvinate, white, the pulvinuli thickish, convex, verrucose, scattered. 
Apothecia small, immersed, crowded.—Cromb. Grevillea, xviii. 
p. 67. 
Differs in the form of the thicker, dispersed thallus, and in the innate 
apothecia, resulting probably from the nature of the habitat. It no doubt 
descends from var. deminuta (Stenh.) Cromb. Journ. Bot. 1885, p. 195, 
and is subconfluent with Hepp, Evs. n. 901 (left-hand specimen). 
Hab. On calcareous rocks in maritime and upland districts.—Distr. 
Only a few localities in Wales, N.W. England, and the N. Grampians, 
Scotland.—B. M.: Mumbles, near Swansea, Glamorgan ; Great Orme’s 
Head, Carnarvonshire; Asby, Westmoreland. Craig Guie, Braemar, 
Aberdeenshire. 
Subsp. 1. L. dissipata Nyl. Bull. Soc. Bot. t. xiii. (1866) p. 368.— 
Thallus macular or indeterminate, very sparingly visible, consisting 
chiefly of a blackish, subleprose hypothallus. Apothecia small, 
pale-livid, slightly white-suffused ; the thalline margin white, opaque, 
subentire or obsoletely crenate; spores ellipsoid, 0,008-12 mm. long, 
0,004-6 mm. thick ; paraphyses not well discrete.—Cromb. Grevillea, 
xvili. p. 67. ; 
A peculiar lichen, the only one which with a state of the type occurs 
in the immediate suburbs of London. In our British specimens, which 
