THE BRYOLOGIST 
Voi.. XXII 
January, 1919 
HYLOCOMIUM ALASKANUM (L. & J.) KINDB.* 
Among a few specimens of mosses lately received from Mr. Maxon, of the 
Smithsonian Institute, was one small lot consisting of_ mostly three closely 
entangled species. Two of these are 
well known, namely Rhytidiadelphus 
triquetrus (L.) Warns., and Drepanocla - 
dus~aduncus (L.) Warns. (. Hypnum 
uncinatum). The other, of which there 
is scarcely more than a few fragments, 
is Hypnum alaskanum L. & J., as given 
in the Manual. This species seems to 
have been scarcely collected or under- 
stood since first obtained by Dali in 
Alaska. Dr. Brotherus, in Engler & 
Prantl, cites it (p. 1060) as a variety 
of Hylocomium pyrenaicum (Spruce) 
Lindb., a species found in Alaska, 
but a very distinct plant in its larger 
size, different branching and pointed, 
plicate leaves. 
H. alaskanum looks at first glance 
more like a small form of Hypnum Sch - 
reberi Willd. than anything else, but 
examination shows it belongs rather 
to Hylocomium , as the stems bear 
numerous, branching paraphyllia and 
the leaves are minutely serrulate all round (the teeth almost too small to be 
seen under a low power) with the margins flat above and strongly reflexed near 
the base. The leaves are not plicate but very concave. The leaf-cells are 
mostly long and narrow, slightly curved, the walls rather unequally thickened 
but not or very slightly pitted. The basal cells are mostly golden brown in 
the stem-leaves, the alar scarcely forming a distinct group. 
It would seem that Dr. Kindberg had specimens of true H. alaskanum 
from somewhere in British America, but at present there are apparently none 
known among the collections at Ottawa. 
R. S. Williams 
Hylocomium alaskanum 
Fig. i. Stem leaf, X36 diam. 
“ 2. Middle branch-leaf, X36 diam. 
“ 3. Median leaf-cells, X320 diam. 
New York Botanical Garden 
*Cat. Can. Plants. 6 : 248. 1892. 
The November number of the BryologisT was published January 15, 1919. 
