10 On the Lichens near New-York. 



4. miniatum. Id. p. 101. Common on rocks. Frond co- 



riaceous and leafy, underneath of a reddish hue. 



5. complicatum. Id. p. 102. Like the preceding, but of a 



dark colour underneath. 



6. Weberi. Id. p. 102. On rocks near waterfalls. Like the 



two last, but the frond is of a thicker consistence, and 

 changes to a greenish colour when moistened. 



II. Class. CCENOTHALAMI. 



Order. I. PHYMATOIDEI. Apothecia included in wart-like 



processes formed from the frond. 



10. POKINA. 



1. pertusa. Id. p. 109. Rocks and old trunks. Common. 



Apothecia with several orifices. 



2. leucostoma. Id. p. 109. On trunks. Apothecia with white 



orifices; crust dark. Resembles a Variolaria. 



3. lejoplaca. Id. p. 109. Rocks and trunks. Apothecia with 



a single and irregular orifice. 



4. fallctx. Id. p. 110. Rough bark. Apothecia with an 



open expanded orifice, like a Lecanora. 



11. Thelotrema. 



lepadinum^ Id. p. 115. On bark. Very common. Pro- 

 bably a new species. Crust yellowish green. 

 12. Ptrenula. 



1. enteroleuca. Sprengel mss. Thelotrema cinereum. Schwz. 

 Very common on trunks. Crust membranaceous, ve- 

 ry white, sublucid, and to the microscope cracked and 

 rugged. Apothecia above the crust, though surround- 

 ed by it at the base, cupuliform, open at the top like a 

 Lecidea; margin black, with a gray bloom ; nucleus 

 hemispheric, whitish with a black pruinose disk. Fig. 3. 



Specimens of this common Lichen were sent by Dr. 

 Torrey to Professor Sprengel of Halle, and by him de- 

 termined to be a new species of Pyrenula, under the 

 name here adopted. It has much the habit of a Leci- 



