36 MR. W. MITTEN—BRYOLOGIA OF THE SURVEY 
H. LENTUM, sp. nov. Dioicum, folis patentibus laxe imbricatis, in 
apicibus ramorum cuspidato-imbricatis, inferioribus latioribus bre- 
vioribus in ramorum medio ubi fructus proferunt late ovatis acumine 
brevi, in ramulis attenuatis ovato-laneeolatis apicibus latioribus obtu- 
sioribus, marginibus tenuiter in ramulinis argutius serrulatis nervo 
ultra medium evanido, cellulis basi ad angulos pluribus latioribus 
angustioribus immixtis parietibus crassiusculis, superioribus angustis, 
quasi apicibus dorso prominulis, in apice oblongis, perichzetialibus 
enerviis e basi ovali amplexante subulatis recurvis subintegerrimis, 
theca in pedunculo unciali scabro ovali cylindracea suberecta inzequali, 
peristomio interno processibus solidis ciliis singulis subzequilongis in 
membrana ad dentium tertiam longitudinis exserta. 
Hab. N.W. coast of America, Douglas. 
Of this moss only a few fragments have been seen. It appears 
to be about the size of the common forms of H. myurum, but of a 
loose spreading habit. 
At first it was supposed that this was only a state of .H. aplo- 
eladum ; but the decidedly rough seta and wider leaves, those of 
the perichetium spreading, render it distinct. The scabrous seta 
of this moss may be considered a new feature in the group of 
species to which it is here referred: but after a consideration of 
the characters which constitute the group Zsotheeium, it becomes 
evident that it cannot be defined distinetly from the groups 
named by Schimper Brachythecium and Scleropodium ; for the 
habit, which is the most evident characteristic of Isothecium, 18 
only more conspicuous among the species forming that group 
than it is in Brachythecium, in which it is essentially the same; 
and the only difference between these groups is the plication of 
the leaves, chiefly when dry, in the group Brachytheciwm, which in 
Isothecium and Scleropodium is less evident, and is thus a transi- 
tion to the group Rhynchostegiwm, which have the leaves more 
smooth. 
(Eurhynehium, Schimp.) 
H. OnEGANUM, Sullivant, in U. S. Expl. Exped. t. 13. H. Douglasii, 
Hook. MS. 
Hab. British Columbia, near the 49th parallel, Lyall; Vancouver 
Island, Wood. 
Some specimens of this noble species were more than a foot long. 
H. pr£eLonGum, Dill. H. Stokesii, Turn. 
Hab. British Columbia, near the 49th parallel, Lyall; Vancouver 
Island, Lyall and Wood. 
This much misunderstood species has a very wide distribution, 
and is found in the Andes. 
