PLATE XXII. 



Figs, i, a-f. Polytrtchum yukonense. 



I, a. Entire plant, natural size. 



I, b, b. Leaves ( X 13)- 



I, c. Transverse section of a leaf ( X34)- 



I, d. Transverse section of a lamella ( X i35)* 



1, e. Pai-t of a lamella seen from side ( X 270). 

 I,/". Basal areolation of the leaf ( X i35)- 



2, a. Polytrichunt jense7t{i. 



2, a. Basal areolation of the leaf ( X i35)- 



3, a-e. Brachythecium beritigianum. 

 3, a. Entire plant, natural size. 



3, b. Stem leaf ( X 26). 



3, c, c. Branch-leaves ( X 26). 



3, d. Basal areolation ( X i35)- 



3, e. Cells in the middle ( X 270). 



4, a-e. Plagiothecium fallax. 



4, a. Entire plant, natural size. 



4, <&. Leaf (X 13)- 



4, c. Perigonial leaf ( X26). 



4, d. Basal areolation of a leaf ( X i35) 



4, e. Areolation in the middle { X I35)- 



5, a-e. Hypnu?n treleasei. 



5, a. Entire plant, natural size. 



5, b, b, b. Leaves ( X26). 



5, d. Basal areolation of a leaf ( X 270). 



■c, e. Cells in the middle ( X 270). 



(366) 



