266 PLANT LIFE OF ALABAMA. 



pine-barren streams are inhabited by a formation of bark lichens, which 

 have their filmy thallus more or less deeply embedded in the smooth 

 bark of hollies, wax myrtles, magnolias, and red bay (Persea), such 

 being the favorite sites of Glyphis achariana, a large array of species 

 of Arthonia and Graphis, Opegrapha tribulodes, nearly every one of 

 the species Trypetbelium and Thelotrema enumerated in the catalogue, 

 and most of Pyrenula, also of 



Gyrostomum scyphuliferum, Buellia t 



JBuellia parasema, Biatora suffuaa 



Buellia subdisciformis, 



all of a strictly southern distribution. Species with a more developed 

 crustaceous, granular, or agglutinated foliaceous thallus, particularly 

 the Southern Heterotheciums, prefer in similar localities the rough 

 bark of old trees. Such are: 



Heterothecium leucoxanthum. Pannaria molybdaea. 



Heterothecium pachycheilum. Pannaria nigrocincta. 



Heterothecium domingense. Physcia crispa. 



Heterothecium tuberculosum. Pyxine sorediata. 



Pertusaria sp. Pyxine picta. 

 Collema nigrescens leioplaca. 



The rough bark of hoary live oaks and of the laurel oak, frequently 

 covered with mosses, is also inhabited by 



Chiodecton rubricinctum. Sticta qnercizans. 



Sticta aurata. Peltigera polydactyla. 



At the base and on the roots of the live oak near the damp ground 

 abound among mosses the webby clusters of the filamentous alga like 

 thallus of Coenoyonium interpositum. In more open and drier situa- 

 tions the trunks and limbs of smaller trees are the home of 



Parmelia tiliacea, Ramallna laerigata, 



Parmelia saxatilis, Ramalina calicaris, 



Parmelia perforata, Cetraria fmdleri, 



Physcia comoaa, Usnea barbata 

 Theloschistes chrysopthalmus flam- 

 cans, 



the last in its several varietal forms. 



In the humid coast plain lichens inhabiting dead wood are frequent, 

 such as 



Lecanora punicea. Lecanora varia. 



Lecanora subfusca. Rinodina flavoniyella. 



Lecanora pallida. Calicium albo-nigrum. 



The most sterile patches of loamy sand are frequently covered with 



Cladonia leporina, Cladonia rangiferina alpestris, 



Cladonia mitrula, Baeomyces roseus; 



and in shady woods, on decaying stumps and rotten trunks, Cladonia 

 pulchella and Cladonia gracilis are common. 



