OF THE FORTY-NINTH PARALLEL OF LATITUDE. 15 



species of the genus Trichostomum allied to T. flavovirens in 

 respect of Tortula : taking for the typical species T. tortuosa, the 

 only difference is in the shorter teeth of the peristome, the 

 structure being identical. The same analogies exist in the 

 development of the peristome of the pleurocarpous mosses, as, 

 for example, in the capsule and peristome of the so-called genera 

 TLomalotlieciwm and Camptothecium. In the species contained in 

 these genera, the resemblance between the plants without the 

 fruit is so great that it requires an expert bryologist to distin- 

 guish them from each other. The same is the case with JPylaiesia, 

 which without fruit or inflorescence could hardly be known from 

 Hypnum cupressiforme. It would seem, therefore, that a natural 

 group of Mosses can only be defined from the structure of the 

 species in which the highest development is found. All those 

 species which agree in all other respects, as habit, ramification, 

 position of the fruit, form, and substance of the leaves, but pre- 

 sent a less development of peristome, should be considered as only 

 affording a negative difference, of barely specific value. There 

 would appear to be no escape from this conclusion among the acro- 

 carpous genera ; and as there is no difference in the structure of 

 the peristome in the pleurocarpous, it must be applicable to the 

 whole group of Arthrodontoid mosses. 



MUSCI. 



DICRANACE^E, Mitten, Musci Ind. 



Ctnodontium, Hedw. 



(Distichium, B. et S.) 



C. CAPILLACEUM, Hedw. 



Hab. Near Fort Ellice, Saskatchewan, and Rocky Mountains, Bourgeau ; 

 Cascade Mountains, Lyall. 



C. inclinatum, Hedw. 



Hab. Saskatchewan, Bourgeau. 



{Leptotrichwri, Hampe.) 



■^ C. FLEXICAULE, ScJlW. 



Hab. Cascade Mountains, Lyall. 



(Dicranella, Schimp.) 



-£ C. crispum, (Dicranum) Hedw. 

 ■"- Hab. Gal ton Mountains, Lyall. 



C. subulatum, (Dicranum) Hedw. 

 Hab. Galton Mountains, Lyall. 





355531. 



