OF WESTERN PENNSYLVANIA 



375 



PLATES 



Explanation of Method of Lettering. 



To facilitate reference and comparison of the various plates 

 a series of letters and figures has been used which applies uni- 

 formly to all of the plates alike. 



Stem-leaf 

 Branch-leaf 

 Perichaetial leaf 

 Paraphyllia 

 Seta 



6, Capsule 



7, Calyptra 



8, Peristome 



3, 



4, 

 5, 



a, Apex 

 an, Annulus 

 B, Branch 



b, Base 



be, Basal median 



c, Central or median 

 cr. Cross-section 



ci f Cilia 



d, Dorsal 

 g, Gemmae 



//;/, Lower margin 



m f Margin. 



p, Lid or operculum 



P, Habit sketch of plant, or of a 



portion of a plant 

 sp, Spores 

 S, Stem 

 s, Peristome-segments 

 t, Teeth 



it pin, Upper margin 

 r, Ventral 



The various letters and figures are used in combination as fol- 

 lows : Iff, apex of stem-leaf; \bc, median basal portion of stem- 

 leaf; 2bc, median basal portion of branch-leaf; 2ad, dorsal view 

 of apex of branch-leaf : Snpni, upper margin of perichsetial leaf, 

 etc. 





