PLcelLaph. 5. IDIOTHALAMEiE. 124?. Variolar. 493 
9. Variolaria clnerea. Grey smallpox-moss . 
Crust round, tartarlike, thin, ash-colour, cracked; cir- 
cumference indeterminate ; apothecia orbicular, very small, 
white, edge raised, soredia white. 
Yariolaria cinerea, Engl. Bot. 241 1. 
On whinstone. 
i 
C. Porid.ze. Thallus crustlike; apothecia wartshape; 
perilhecium distinct. 
IV. 125. PYRENULA. Acharius. Nut-moss . 
Thallus crustlike, flat, expanded, adnate, uniform; apo- 
thecia wartshape, formed of the thallus, enclosing or sur^ 
rounding at the base a single thalamium, with a simple, 
thick, black, nippled perithecium covering a globular, cell- 
bearing throughout nucleus. 
a. Apothecia open at the mouth , or surrounding a naked 
thalamium. 
1 . Pyrenula umbonata. Button nut-moss . 
Crust tartarlike, regular, very finely cracked, greyish- 
red; apothecia bald, reddish, rather depressed above, slightly 
surrounding the rather prominent, nipplelike opening of 
the thalamium. 
Verrucaria thelostoma, Achar. in Winch. Bot. Guide , 2,44. 
Lichen thelostomus, Engl. Bot. 2153. 
Pyrenula umbonata, Achar. Lich. 316. 
On whinstone. 
b. Apothecia closed , strictly surrounding the prominent 
nipple , or thalamium , hut without forming a border . 
2 . Py renula tessellata. Tessellated nut-moss . 
Crust tartarlike, uneven, cracked in beds, yellowish-grey ; 
apothecia enlarged at bottom, depressed, closed, strictly 
surrounding the prominent part of the thalamium, which 
is terminated above by a slightly bordered mouth. 
Lichen tessellatus, Engl. Bot. 533. 
Verrucaria fuscella viridula, Achar. Lich. 290. 
Verrucaria tessellata, Achar. Meth. 115 ; Lich. 2S9, 
Pyrenula tessellata, Achar. Syn. 126. 
On brick-walls and stones. 
