GENERA ANt) SPECIES. 81 



the affinities of the various groups are referred to more 

 complete works on the subject. It is intended to devote 

 most attention to the description of the species, dwell- 

 ing particularly ui)on the points of liistorical interest, 

 thus rendering the subject less dry and monotonous. 



An attempt has been made to arrange the genera and 

 species in a natural order beginning with the lowest. 



/. CALICIACE^. 



With comparatively few exceptions, the representa- 

 tives of this family are insignificant in appearance. 

 The thallus is either crustose or fruticose. The 

 apothecia are globose and terminal upon the stipes 

 or on the branches of the fruticose thallus. A stipe is 

 a small, simple, erect stalk devoid of algae, hence is not 

 a part of the thallus ; it is an apothecial stalk bearing 

 the apothecia. 



Upon an examination of the Caliciaceae, it will be 

 found that the spore-sacs dissolve and set free the im- 

 mature spores which lie above the thecium and are 

 covered over by the exciple (proper exciple). Finally, 

 there is a rupture of the apical portion of the apothe- 

 cium, setting free the spores. 



None of the representatives of this family have any 

 special historical interest. 



KEY TO THE GENERA. 



Thallus crustose. 

 Apothecia terminal on slender stipes. 



Spores simple, colorless 1. Coniocyhe. 



Spores two-celled, dark 2. Calicium. 



Spores simple, dark 3. Ci/p/ielium. 



Apothecia sessile ; spores two-celled, dark, 4- Acolium. 

 Tliailus rigidly fruticose, terniiual apothecia, 5. Splui^rophorus. 



