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 Trypethelium and Thelotrema enumerated in the catalogue, 
and most of Pyrenula, also of— 
Gyrostomum scyphuliferum, Buellia subpostumum, 
Buellia parasena, Biatora suffusa— 
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 nigrocineta. 
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 
xovered with mosses, is also inhabited by— 
Chiodecton rubricinetum, Sticta quercizans. 
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 Coenogonium interpositum. In more open and drier situa- 
tions the trunks and limbs of smaller trees are the home of— 
Parmelia tiliacea, Ramalina laevigata, 
Parmelia saxatilis, Ramalina calicaris, 
Parmelia perforata, Cetraria fendleri, 
Physcia comosa, Usnea barbata— 
Theloschistes chrysopthalmus flavi- 
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 flavonigella. 
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. 
