164 GUIDE TO THE STUDY OF LICHENS. 



ing been besprinkled with a mealy substance. Color 

 varies from yellowish to grayish-green or bluish-gray. 

 Apothecia, when present, are quite large, discoid, often 

 bearing filiform thalloid branches. Disk of a different 

 color from the thallus. The spores are small, simple, 

 oval, colorless ; resembling those of Cetraria. 



1. Evernia furfuracea. Thallus large, much 

 branched, foliose, but pendulous upon branches of 

 trees ; bluish-green, tinged with gray ; channelled 

 below, light-gray. Usually sterile. Apothecia not 

 seen. 



This lichen is striking in appearance and in the 

 eastern states occurs almost wholly upon pine trees in 

 mountainous districts. It is a handsome, soft, pliable 

 plant, which is only very loosely attached to the 

 branches of the tree. Some authors place it in the 

 group Physcia, 



This species was at one time highly recommended as 

 a substitute for quinine. It yields a red dye. The 

 Egyptians at one time employed it in the making of 

 bread and in the preparation of hair-powders. 



2. Evernia vulpina. Thallus large, typically fruti- 

 cose, branches angular, ridged, thickness of branches 

 decreasing toward the top ; lemon color. Apothecia 

 very large, terminal tendency, margin and lower sur- 

 face bearing thalloid filaments. Disk brown, concave. 

 Spores colorless, elliptical, simple, 7.5/x X 5.5^. 



This is the noted "Ulf-mossa" (Wolf's moss) of 

 the Swedes. It was so named from the popular belief 

 that the plant was poisonous to wolves. The lichen 

 was powdered and mixed with powdered glass ; the 



