404 LICHENACEI, [LECANORA. 
subimbricatus Relh. Fl. Cantab. 1785, p. 427; With. Arr. ed. 3, 
iv. p. 18. 
The thallus is small or moderate (1-4 inches in diameter), often 
greyish-brown, rarely somewhat leaden-coloured, and at times in old 
plants becomes centrifugal. In some situations the thallus is reddish- 
grey with the apothecia brownish-red, when it seems tu be var. 8. myr= 
rhina Fr. (non Ach.) Lich. Eur. p. 124; Cromb. Grevillea, xviii. p. 47. 
This, however, evidently arises: from its being suffused either with 
pee of iron or with urine, so that it is only an accidental state. Our 
ritish specimens are well fertile, the apothecia, Hueneh central, being 
numerous, occasionally crowded and then subangulose. The spermogones 
are frequent, dark-brown, with simplish sterigmata and spermatia 
0,006-7 mm. long, about 0,001 mm. thick. 
Hab. On rocks and walls, usually on the coping of bridges, in lowland 
and upland districts—Distr. Here and there throughout England, in N, 
Wales, reported also from §.W. Scotland (Cathkin); very rare in the 
Channel Islands; not seen from Ireland.—-B. M.: Island of Guernsey. 
Bury St. Edmund’s, Suffolk; Clare Hall Bridge, Cambridge ; near Stroud, 
Gloucestershire ; Hale’s End, Malvern and Pershore Bridge, Worcester- 
shire ; near Congerstone, Leicestershire ; Oversley Bridge, Warwickshire ; 
Garn Bridge, Conway Castle, Denbighshire; Barnard Castle and Negle- 
stone, Durham; Kirkby Lonsdale, Westmoreland. 
79. L. circinatula Nyl. Flora, 1883, p. 100.—Thallus small, ap- 
pressed, diffract, radiately divided at the circumference, the radii 
plane, dark-greyish or brownish-grey (K+ yellow, CaCl—). Apo- 
thecia innate, submoderate, plane, dark-brown, the thalline margin 
thin, entire; spores 8nz, ellipsoid, about 0,007 mm. long, 0,005 mm. 
thick ; paraphyses thickish, jointed ; hymenial gelatine bluish, then 
tawny wine-red with iodine.—Cromb. Grevillea, xii. p. 89. 
Closely allied to Z. ctrcinata, from which it is distinguished by 
the different reaction and by the smaller thallus and spores. The apo- 
thecia are numerous and crowded except at the immediate circumference. 
The spermogones have the sterigmata slender, 2-3-jointed, with straight 
bacilliform spermatia, 0,0035-45 mm. long, 0,0005 mm. thick. 
Hub. On siliceous stones in a maritime district—Distr. Only very 
sparingly in S. England.—B, M.: Near Beachy Head, Sussex. 
E. Apothecia lecanorine or at times biatoroid; spores &ns, very 
rarely 8-16nz, simple, rarely 1-septate, colourless; hymenial 
gelatine variously tinged with iodine. Spermogones with 
simple sterigmata and acicular, arcuate, very rarely straight 
spermatia. f 
a. Thallus normally subeffigurate, K—. 
80. L. galactina Ach. Lich. Univ. (1810) p.424.—Thallus snb- 
orbicular, appressed, yerrucoso-diffract, lobato-crenate at the circum- 
ference, opaque, subpulyerulent on the surface(K—). Apothecia 
moderate, or somewhat small, adnate, somewhat plane, pale- or 
brownish-testaceous, white-pruinose or naked, the thalline margin 
at length crenulate and often flexuose ; spores ellipsoid or oblong, 
