317 Two NEW Species of Grimmia from Montana 



quadratic to twice longer than broad, towards costa becoming 2- 

 4 times longer than broad : cells apparently never distinctly sinu- 

 ous walled : sections of leaf show costa with two large cells on 

 ventral side and two rows of somewhat smaller cells on dorsal 

 side : lamina of leaf is of one thickness of cells, usually wnth one 

 or two rows doubled near costa, or sometimes somewhat distant 

 from costa, but not doubled in margin : occasionally the leaf is 

 hyaline nearly y^ down from apex, the hyaline cells always elon- 

 gated : evidently dioicous : sporophyte not seen. 



Specimens of type collected near Neihart, Belt Mts., Mont., 

 Sept. 21, 1 89 1, also obtained at Marsh Lake and Dawson on the 

 Yukon River. 



Hxplanation of Plates 



Plate 19. Grimmia Brittoniae 



1. Plant about natural size. 



2. Upper leafj X about 35 diam. 



3. Lower stem leaf, X 35 diam. 



4. Section of leaf, X ^75 diam. 



5. Part of perichaetiuni. 



6. Median cells, X 35° diam. 



7. Basal cells. 



8. Apex of leaf from upper side, X ^75 diam. 



9. Inner perichaetial leaf. 



Plate 20. Grinunia ienuicaulis 



1. Plants about natural size. 



2. Upper stem leaf, X about 35 diam. 



3. Lower stem leaf, X about 35 diam. 



4. Part of perichaetium. 



5. Median cells, X 35° diam. 



6. Basal cells, X 35° diam. 



7. Apex of leaf from below, X ^75 diam. 



8. Section of leaf, X ^75 diam. 



9. Section of leaf lower down, X ^75 diam. 



