8 
rectly referred by Nyl. to this species, of which it has the lobation 
and the appressed habit. The lobes of P. perforata, as I have seen 
it, are always free at the margin, and more or less ascendant. 
7. P. Borreri, Tuck. On trees and rarely on rocks, seldom fer¬ 
tile. 
b. rudecta, Tuck. On trees. According to Nyl., Pyr. Or. 
edit. 1891, p. 49, the spermatia of b differ from those of a , and he 
considers them distinct. 
8. P. saxatilis, (L.) Fr. On rocks and trees, common. 
b. sulcata , Nyl. On stones in walls. 
9. P. physodes, (L.) Ach. On trees and stones. Seldom fertile. 
10. P. pertusa, (Schrank.) Schaer. On trees and rocks. Rare 
and sterile. I have a fertile specimen from Nova Scotia, sent by Prof. 
Rothrock. Tuckerman does not seem to have seen the American 
plant in this condition. 
11. P. colpodes, (Ach.) Nvl. On trees, mostly in low places. 
My largest specimen is 54 inches in its longest diameter. Exsic., 
Lojka, n. 112. 
12. P. olivacea, (L.) Ach. On trees and rails, sterile. 
b. prolixa , Ach. Cornell’s ledge, Dartmouth, 1879, fertile. 
e. sorediata , (Ach.) Nyl. On stones, sterile. 
13. P. caper at a, (L.) Ach. On stones and trees, common. 
14. P. eonspersa, (Ehrh.) Ach. On rocks and rails, common. * 
15. P. ainbigua, (Wulf.) Ach., c. Ha lei, Tuck. On cypress in 
swamps, 1863. Rare. 
8. PHYSCIA, (DC., Fr.) Th. Fr. 
1. P. speciosa, (Wulf., Ach.) Nyl. On rocks and trees. Only 
once found fertile. 
2. P. hypolcuca, (Muhl.) Tuck. On trees. Rare. Also in 
Weymouth. A form occurs in which the thallus is lemon-colored 
beneath. 
3 - !*• leucoitiela, (L.) Michx. On oak in woods in the north 
part of the city, 1SS5. Only a single sterile specimen found. 
4. P. aqnila, (Ach.) Nyl., b. detonsa , Tuck. On trees and 
rocks. Exsic., Lojka, n. 122, 
