448 111. Placod. 4. CENOTHALAMEiE. PLcelLaplu 
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, 25 ; Engl. Bot. 1941. 
Lichen subimbricatus, Relhan Cant. 459. 
Lobar ia radiosa, Hoffm. Germ. 157. 
Parmelia circinata, Achar. 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 ; apothecia depressed 
in the centre, red ; thalloid border thick, raised, not cut. 
Lichen gelidus, Lin. Mnnt. 133 ; Engl. Bot. 699. 
Lichen Hecloe, FI. Dan. 470. 
Parmelia gelida, Achar. Meth. 188. 
Lecanora gelida, Achar. Lich. 428. 
On rocks. 
Thalloid 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. 7,27. 
Parmelia dispersa, Achar. 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 ; 
apothecia saucershape, thick, adnate, sessile ; proligerous 
Jlake forming the centre, plano-convex, coloured, covering 
the apothecium above; inside cellular, streaked; thalloid 
border rather thick, colour of the thallus, nearly free. 
