PLATE XXII. 



Figs, i, a-f. Polytrichum yukonense. 



i, a. Entire plant, natural size. 



i, b, b. Leaves ( X I 3)- 



i, c. Transverse section of a leaf ( X 34)- 



i, d. Transverse section of a lamella ( X x 35)- 



i, e. Part of a lamella seen from side ( X 2 7°)- 



i,/. Basal areolation of the leaf ( X 135)* 



2, a. Polytrichum jensenii. 



2, a. Basal areolation of the leaf ( X x 35)- 



3, a-e. Brachythecium beringianum. 

 3, a. Entire plant, natural size. 



3, b. Stem leaf ( X 26). 



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



3, d. Basal areolation ( X I 35)- 



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 ( X 26). 



4, d. Basal areolation of a leaf ( X J 35) 



4, e. Areolation in the middle ( X 135)- 



5, a-e. Hyfinum treleasei. 



5, a. Entire plant, natural size. 



5, b, b, b. Leaves ( X 26). 



5, d. Basal areolation of a leaf ( X 2 7 )- 



5, e. Cells in the middle ( X 2 7°)- 



(366) 



