| 250 Lichenes of New England. 
and tawny on the under side. Scutelle large, disk 
golden-yellow, border thin and waved. 
Pracópivu, De Cand., Feé, Hooker. . The leafy Le- 
cidee and Lecanore, are arranged in three genera by 
Hooker, and form together the natural family Squama- 
ries. The present genus has “the fructification: of 
.Lecidea, with the thallus of Squamaria.” We have a 
plant in this neighborhood, which seems to present all 
the characters of Placódium, while I do not find any 
specific description answering to.it. It may be described 
as having an imbricated thallus of small lobules; the 
lobules somewhat regularly trifid, with rounded apices, 
and raised margins ; the patéllulz small, black, solitary, 
in the centre of each lobule: This curious plant pre- 
sents very little to the. naked eye, beside a loose black 
crust. On every specimen that I have examined, I 
I have found (beside the apothecia) regular heaps of 
brownish grains or globules, which: may be propagula, 
or possibly parasitick. On ledges in Brookline, in cóm- - 
pany with Shinnen guise. «, abundant. 
r Santis conspérsa, b Meth. ete., Muhl., Tort; 
Hals. ; omitted in the Mass. Catalogue, but common on 
walls and stones, in this vicinity. 
P. pariétina, Ach. Meth., Scher !, Hook., Mass. Cat, - 
Lichen pariétinus, L., and: E. Bot. t. 194, and PP. 
rutilans and. auréola, Ach. (sec. Spreng.), P. rütilans 
Hals.?, P. ritilans, Esa t pois mendes buildings &e. 
very common. 
To this lichen, eed cites Meyer as tearing a 
number of forms now located in different genera. And 
it is stated in Lindley’s Introduction, that Meyer’s con- 
