LICHENES. 73 



niatod, or compressed and subangulate. Apothecia orbiculate, 

 with an inflexed thallodal border, the disk concave, coloured. 



9. Ramalina. Thallus cartilaginous, branched and laci- 

 niated, compactly cottony within. Apothecia orbiculate, bor- 

 dered ; the disk and border of the substance of the thallus, and 

 of one colour. 



b. Thallus cylindrical. 



10. Usnea. Thallus cartilagineo-crustaceous, cylindrical, 

 hollow, enclosing a central thread. Apothecia orbiculate, en- 

 tirely formed of the thallus, and of the same colour. 



11. Alectoria. Thallus cartilaginous, the branches subfili- 

 form, subfistulose, cottony within. Apothecia orbiculate, thick, 

 marginate, at length convex and losing the border, entirely 

 formed of the thallus, and of the same colour. 



12. Cornicularia. Thallus cartilaginous, branched, some- 

 what solid and cottony within. Apothecia orbiculate, obliquely 

 peltate, entirely formed of the substance of the thallus, and of 

 the same colour. 



C. Apothecia without footstalks. 



* Apothecia, tubercles, immersed. 



13. Verrucaria. Thallus crustaceous or cartilagineo-mem- 

 branaceous, uniform. Apothecia subglobose, partly immersed, 

 of a different colour and substance from the thallus, enclosing 

 a nucleus, the apex papillose, usually perforated. 



14. Endocarpon. Thallus cartilaginous or foliaceous, often 

 lobed. Apothecia globose enclosed in the thallus, with a mar- 

 ginated dusky perforation at the apex, enclosing a nucleus. 



15. Porina. Thallus cartilagineo-membranaceous, uniform. 

 Apothecia verruciform, formed of the thallus, one or many 

 celled ; each cell containing a nucleus, and opening by a per- 

 foration above, coloured, often distorted. 



16. Thelotrema. Thallus cartilaginous, membranaceous or 

 subcrustaceous. Apothecia verruciform, formed of the thallus, 

 hollowed, marginated, containing a nucleus beneath a coloured 

 disk. 



* * Apothecia, (lirellce,) sublinear. 



17. Syncesia. Thallus crustaceous. ApotJiecia oblongo- 

 elongate, stellato-radiate, aggregated and immersed in scattered 

 thallodal warts. Perithecium none. Lamina proligera pellucid, 

 supported on opaque vertical layers. 



18. Arthonia. Thallus crustaceous or cartilagineo-mem- 

 branaceous, uniform. Apothecia roundish, elongated or varying 



i 



