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POPULAR HISTORY OF LICHENS. 



margins; and var. deusta, in which the thallus is greyish- 

 fuliginose and rugose, with naked margins. These varieties, 

 with their sub-varieties, include the Gyrophora cylindrica 

 and proboscidea of older authors. They are comparatively 

 common on the granitoid rocks of the summits of many of 

 our Highland mountains ; we have met with them also at 

 comparatively low elevations, as on a wall on the slope of 

 a hill a few hundred feet above the mineral well at Inver- 

 leithen, Peebles-shire. The var. deusta usually occurs at 

 higher elevations than var. cylindrica. The spermogones of 

 this species are frequently abundant, and their presence is 

 indicated by scattered, small, black grains resting on a 

 slight circular elevation formed by their bodies. They are 

 globular or ovoid, depressed or conical; their constituent 

 elements or contents resemble those of U. vettea. The 

 thecse are eight-spored, not large, but very delicate; the 

 spores are also delicate, oval, simple, usually colourless. 

 Sometimes they appear double-walled, have a faint yellow 

 shade, exhibit granular contents with a slight septate divi- 

 sion, and have more of an ellipsoid or oval-oblong form. 

 They are much alike in all the species and varieties which 

 we have examined from home and foreign localities, with 

 the exception of U. pustulata. Some varieties, probably 



