OF THE FORTY-NINTH PARALLEL OF LATITUDE. 19 



In pale-green tufts, to all external appearance like D. Mougeotii, 

 (AmpJioriditm) Schimp., but leaves gradually narrowed into an 

 acute point, and the margin remotely serrulate as in D. cyathi- 

 carpus, {Zygodon) Mont. ; the cells of the base of the leaf are not 

 linear and narrow as in that species. 



All the above-named species are regarded by me as imperfectly 

 peristomate forms of JRhabdoweissia, Schimp., which is itself com- 

 posed of species passing into the complete forms observable in 

 D. poly carpus, J), virens, and D. Wahlenbergii. 



(Ceratodon, Erid.) 

 D. purpureus (Linn.). 



Hab. Lake Winnipeg, Bourgeau; Cascade Mountains, British Columbia, 

 and Vancouver Island, Lyall. 



{Oncophorus, Brid.) 



D. polycarpus, (Dicranum) Ehrh. 



Hab. Cascade Mountains, Lyall; Saskatchewan, Bourgeau. 



D. virens, (Dicranum) Hedw. 



Hab. Galton Mountains, alt. 6000-7000 feet ; British Columbia, Lyall. 



D. Wahlenbergii, Brid. 



Hab. Saskatchewan, Bourgeau. 



No species of Didyniodon of the section Leptodontium, Hampe, 

 has yet been received from British N. America ; but the Syrrhopodon 

 excelsus, Sullivant, referred by Muller to Zygodon, appears to be a 

 slender state of a species which has been sent in a fertile state 

 from Mexico, and corresponds nearly with the description of Tri- 

 chostomum ulocalyx, C. Muller. 



GKIMMIACEA 



G-rimmia, Uhrk. 

 (Scouleria, Hook.) 



G. Scouleri, C. Muller. 



Hab. On stones in the Columbia River, Fort Colville, Lyall. 



(Schistidiwm, Brid.) 

 G. apocarpa (Linn.). 



Hab. Rocky Mountains, Bourgeau ; Cascade Mountains and Fort Col- 

 ville, Lyall; N.W. America, Douglas. 



Generally distributed in British N. America; and from the 

 numerous specimens brought by Mr. Taylor from Davis's Straits, 

 it would appear to be abundant in that region. Amongst his 



c2 



