196 HERRE 



3. PARHELIA SAXATILIS (L.) Ach. 

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

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

 Parmelia saxatilis Tuck. Syn. N. Am. Lich. I: 59. 1882. 

 Parmelia saxatilis Herre, Proc. Wash. Acad. Sci. 7: 354. 1906. 

 Lichen omphalodes L. Sp. Plant. 1143. 1753. 

 Parmelia omphalodes Ach, Meth. Lich. 204. 1803. 



Thallus narrowed, deeply cleft; lobes long, sinuous, more or less 

 pinnately dissected, or sometimes rather simple and irregularly cut- 

 lobed; surface reticulate, rimose, at length sculptured andlacunose; 

 often scabrous, becoming isidiophorous; color usually ashy gray, but 

 varying from almost white or green to even a yellow-gray; beneath 

 black, with paler or chestnut tips to the lobes; usually densely 

 clothed with black fibrils; KOH yellow; medulla first yellowish, soon 

 blood-red; CaCl202 — . 



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



sub-crenulate or rather entire; in my specimens greenish powdery 



7.5—9 

 sorediose; spores ellipsoid, ,«• Practically always sterile with 



us. Of several thousand specimens examined in the field, but one 

 was found fruiting. This was growing in Devils Canon on sand- 

 stone, alt. 2300 feet, the specimen having 12 apothecia. 



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

 cends as low as 150 feet, but becoming very abundant as the moun- 

 tains are ascended. Grows indifferently on dead or live trees and 

 rocks, but reaching its maximum size on moss-covered sandstone. 



The variety Isidiata Anzi, distinguished by the isidiose sur- 

 face of the fronds, which are reduced to an almost uniform crust, is 

 not rare in the higher mountains, growing on sandstone. 



The variety Omphalodes (Linne) regarded as a species by 

 many authors, occurs rarely on sandstone along the highest peaks. 

 It is distinguished by the dark, purpHsh-brown to blackish color of 

 the thallus. 



A hchen of Europe, Asia, Africa, and North America. 



4. PARMELIA HERREI A. Zahlbr. 



Parmelia herrei A. Zahlbr., in litt. 



Parmelia herrei Herre, Proc. Wash. Acad. Sci. 7: 353. 1906. 



