no 



Stipes or podetia wanting. 



Apothecia cup-shaped, flattened or convex. 



III. Lecideaceae. 

 Apothecia irregular, linear or stellate; thallus crusta- 



ceous, mostly hypophloeodal IV. Graphidaceae. 



Thalloid exciple present, or apothecia immersed in the thallus. 

 Apothecia discoid, sessile, rarely immersed. 



Plasmic masses of spores united ; spores two-celled. 



V. Physciaceae. 



Plasmic masses not united VI. Parmeliaceae. 



Apothecia closed, hypophloeodal or immersed in the thallus; 

 paraphyses very slender or gelatinized... VII. Verrucariaceae. 

 Symbiotic algae belonging to the Cyanophyceae. 1 



Algae belonging to the genus Nostoc, except in Hydrothyria, thallus 



foliose, dark blue, thin VIII. Collemaceae. 



Algae not belonging to Nostoc.. ..IX. Pannariaceae. 



o o o 



GENERAL DESCRIPTION OF PLATES. 



In order to avoid unnecessary repetition there is here given a gen- 

 eral description of the plates illustrating the lichen-genera of the ter- 

 ritory. With a few exceptions each plate illustrates one genus. 

 Plate 15 shows the spore-sacs, spores and paraphyses of low forms 

 of lichens, the apothecial and thalloid characters of which are suffi- 

 ciently well illustrated in the plates of related genera. 



The sequence of the figures illustrating the different structures is 

 the same in most of the plates, that is, beginning with the upper 

 left hand corner the plant is shown natural size, sometimes followed 

 by a figure of a plant or portion of a plant somewhat magnified (C. 

 ocular and i in. obj.) ; next follow the figures illustrating the 

 structure of the apothecium and thallus, the drawings being made 

 from hand-sections mounted in water (C. ocular, i obj. and camera 

 lucida) ; the spore-sac and paraphyses as well as the spores and 

 algae are more highly magnified (C. ocular, -Jj- in., water-immer- 

 sion, and camera lucida). 



Coloration of the hyphal tissue is indicated by shading. 



Family I. CALICIACEAE. 



There is little doubt that this natural and distinct group contains 

 the lowest lichen-types. In fact the majority of the genera have 



1 The following genera of the Pannariiiccae have bright green algae : Nephro- 

 iinuw, Solorfna, Sficfa and Psoroma. 



