354 



HERRE 



clean appearance ; beneath black ; densely clothed with small 

 black fibrils. Apothecia abundant, mostly central ; disk bright 

 chestnut ; margin entire, crenate, or crenulate, or even lobed. 

 This beautifully colored lichen is very abundant on oaks and 

 buckeyes at an altitude of 2000 feet and upward. It occurs in 

 special abundance about the summit of Black Mountain, at an 

 altitude of 2780 feet. Wherever found it is in full fruit. 

 Lichen tiliaceus Hoffm. Enum. 26, -pi. 16, f. 2. 1784 ; in part. 

 Parmelia tiliacea Acharius, Meth. Lich. 215. 1803. 



6. PARMELIA SAXATILIS (L.) Ach. 



Thallus narrowed, deepl}' cleft; lobes long, sinuous, more or 

 less pinnately dissected, or sometimes rather simple and irregu- 

 larly cut-lobed. Surface reticulate, rimose, at length sculptured 

 and lacunose ; often scabrous, becoming isidiophorous ; color 

 usually ashy gray, but varying from almost white to green or 

 even a yellow-gray ; beneath black, with paler or chestnut tips 

 to the lobes ; usually densely clothed with black fibrils. Apo- 

 thecia small to medium ; disk pale chestnut ; margin irregular, 

 sub-crenulate or rather entire ; in my specimens greenish 

 powdery sorediose. Practically always sterile with us. Of 

 several thousand specimens examined in the field but one was 

 found with fruit. This was growing in Devils Canon on sand- 

 stone (altitude 2300 feet), the specimen having 12 apothecia. 



Common on trees and rocks. Rarer in the foothills, where 

 it descends as low as 150 feet, but becoming very abundant as 

 the mountains are ascended. Grows indifferently on dead or 

 live trees and rocks, but reaching its maximum size on moss- 

 covered sandstone. 



While there is considerable variation in color, texture, and 

 width of the fronds, all our plants seem to be referable to the 

 type form. 



Lichen saxatilis L. Sp. PI. 2 : 1142. 1753. 

 Parmelia saxatilis Ach. Meth. Lich. 204. 1803. 

 Parmelia saxatilis Fries, Lich. Europ. Reform. 61. 183 1. 



7. PARMELIA PHYSODES (L.) Acharius. 

 Thallus suborbicular, deeply cut, more or less inflated 

 loosely attaclied to the substratum ; lobes numerous, sinuous 



