4 
OF THE FORTY-NINTH PARALLEL OF LATITUDE, 19 
. In pale-green tufts, to all external appearance like D. Mougeotii, 
(Amphoridium) 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 Rhabdoweissia, Schimp., which is itself com- 
posed of species passing into the complete forms observable in 
D. D. polycarpus, D . virens, and D. Wahlenbergit. 
(Ceratodon, Brid.) 
- 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, A 
D. WAHLENBERGIIL, Brid. e 
Hab. Saskatchewan, Bourgeau. F 
No species of Didymodon of the section ee Hampe, 
has yet been received from British N. America; but the Syrrhopodon 
excelsys, Sullivant, referred by Müller 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. Müller. 
GRIMMIACEX. 
GRIMMIA, Ehrh. 
(Scouleria, Hook.) 
G. ScouLeErı, C. Müller. 
Hab. On stones in the Columbia River, Fort Colville, Lyall. 
(Schistidium, Brid.) 
DG 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 
ee c2 
