THE LICHEN-FLORA OF CHICAGO AND VICINITY. 37 



. Gfaphis, (Ach.) Nyl. This genus has been fully discussed by 

 Nylander, who followed the thought of Acharius, and by 

 Tuckerman, in his Genera Lichenum, 203; Syn Pt 2. 119. 

 Thallus crustaceous, uniform; apothecia mostly lirellaeform, 

 and branching, but in some species rounded, difform; the 

 proper exciple colored or black. Differentiated from Ope- 

 grapha by the spores. 



100. G, scfipta, (L.) Ach. Thallus thin, whitish, even or rugose, 

 sub-tartareous; apothecia immersed or half immersed, slender, 

 width uniform, simple or branched, obtuse at ends; proper 

 margin narrow, wavy; thalloidal margin tumid. Spores color 

 less. 



Common everywhere on oaks, hickories and other trees; 

 apothecia variously branched. There are a number of 

 varieties which may occur here. 



101. G. dendritica, Ach. Thallus white or yellowish, thin, pul- 

 verulent; apothecia brownish black, immersed^ broad, flexuose- 

 branched, forked; disk broad, often caesio-pruinose; margin 

 thin. 



On oaks and various trees within our limits. These two spe- 

 cies seem to be the only ones of this genus in northern Illi- 

 nois. One other can be added for the southern portion of 

 the State. When compared with the exuberance of forms 

 in Florida, derived, however, from semi-tropical or tropical 

 sources, this is a small number. The limitation of species is 

 well illustrated by tracing this genus from south to north. 



FAMILY 10. GLYPHIDEI. 



Afthonia, (Ach.) Nyl. This genus, containing a great number of 

 species mostly tropical, is one of the most perplexing. Dr. 

 Nylander, more than twenty years ago, described about one 

 hundred species. Henry Willey in his " Synopsis," published 

 in l8go, admits three hundred and forty-eight species, and 

 mentions a few more that he had not seen. About eighty of 

 these are from the United States, four or five of which were 

 discovered by the author. The genus should have been 

 spelled Ardonia, according to its derivation from the Greek, 

 but long usage has sanctioned the present spelling. The 

 genera Chiodecton and Glyphis, which immediately precede 



