Two new Species of Grimmia from Montana 



317 



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 with one 

 or two rows doubled near costa, or sometimes somewhat distant 



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



_ _ _ m 



hyaline nearly 



down from apex, the hyaline cells always elon- 



gated : evidently dioicous : sporophyte not seen. 



M 



^eihart, Belt Mts., Mont., 

 Lake and Dawson on the 



Yukon River. 



Explanation of Plates 



Plate 19. Grimmia Brittoniae 



1. Plant about natural size. 



2. Upper leaf, X about 35 diam. 



3. Lower stem leaf, X 35 diam. 



4. Section of leaf, X x 75 diam. 



5. Part of perichaetium. 



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. Grimmia temdcaulis 



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. 



