448. 111. Placod. 4. CENOTHALAMEZK.. PI. cell. aph. 
6. Placodium circinatum. Compass placodium. 
Crust cracked in beds, greyish white; circumference 
rayed, plaited, linear, jagged; apothecia very crowded, at 
length angular; centre with innate beds, flat, ‘brown-black ; 
thalloid edge nearly even. 
Lichen radiosus, Hoffm. Lich. 4, 6: 
Lichen circinatus, Persoon in Uster Ann. 7,253 Engl. Bot, 1941. 
Lichen subimbricatus, Relhan Cant. 459. 
Lobaria radiosa, Hoffm. Germ. 157. 
Parmelia circinata, 4char. Meth, 189. 
Lecanora circinata, Achar. Lich, 425. 
On limestone.. 
7. Placodium gelidum. Cold placodium. 
Crust cracked, flesh-grey; circumference rayed, jagged ; 
central wart brown, radiately wrinkled ; apochecta depressed’ 
in the centre, red; ¢hallotd border thick, raised, not cut. 
‘ Lichen gelidus, Lin. Mant. 1335 Engl. Bot. 699. 
Lichen Hecle, Fl. Dan. 470. 
Parmelia gelida, Achar. Meth. 188. 
to) 
Lecanora gelida, Achar. Lich. 428. 
On rocks. 
Thailoid wart in the centre very singular, it probably 
should form a separate genus. 
8. Placodium dispersum. Dispersed placodium. 
Crust dispersed, granulated, unequal, nearly grey, some- 
times very small; apothecia scattered; centre flattish, pale 
brown-grey, and black; thalloid border raised, thin, cre- 
nulated. 
Lichen crenulatus, Dicks. Crypt. 5,9; Engl. Bot, 930. 
Lichen dispersus, Persoonin Ulst. Ann, T, 27. 
Parmelia dispersa, char. Meth. 169. 
Lecanora galactina dispersa, Achar. Lich. 424, 
On walls, stones, and limestone rocks. 
XXII. 112. RINODINA. Acharius. Rinodine. 
Thallus crustaceous, flat, expanded, adnate, uniform ; 
apothecta saucershape, thick, adnate, sessile; proligerous 
flake forming the centre, plano-convex, coloured, covering 
the apothecium above; inside cellular, streaked; thalloid 
border rather thick, colour of the thallus, nearly free. 
