44 Rhodora [MARCH 
intermediate between L. polycarpa and L. obscura, in some of its 
forms approaching the former, in others the latter, but can hardly 
be included under either as a variety. From L. polycarpa, according 
to Best, “it differs by its smaller, straight leaves which are shorter 
and comparatively broader, usually gradually acute and blunt pointed, 
and by its shorter, often imperfect segments.” From L. obscura it 
may be distinguished by its thinner-textured, symmetric leaves which 
are lightly biplicate and often revolute at the margins. It is widely 
distributed, ranging throughout the United States east of the Rocky 
Mountains, but is rare in Canada and in the Southern States. The 
spores mature in summer. 
AMBLYSTEGIUM VACILLANS Sull. Attached to rocks, usually 
submerged, in a rapid brook, Hamden (1909) and New Haven! 
(G. E. N.). Determination confirmed by Dr. Grout. The type 
locality for this species is the White mountains, New Hampshire, 
where it was collected by Oakes. It is also recorded from Vermont 
(Grout). A. vacillans has the habit and general appearance of A. 
riparium to which it is closely related. It may be identified by the 
usually obtuse tips of the leaves, which have short, frequently irregu- 
lar cells in the apical region. The range of this species is certainly 
more extensive than the small number of localities from which it has 
been reported would seem to indicate. Outside of New England it is 
definitely known only from Ontario and New Jersey. Doubtless, 
as in the present case, it is often collected for A. riparium and not 
examined with sufficient care. The writer ventures the opinion that 
if all herbarium material bearing the label “ A. riparium” be reéxam- 
ined our knowledge concerning the distribution of A. vacillans will be 
considerably increased. Since it usually seems to be regarded as a 
subalpine plant it is of interest to note that the New Haven station 
is less than ten feet above tide water. 
CALLIERGON TRIFARIUM (Web. F. & Mohr) Kindb. Partly sub- 
merged in an open, marly swamp at the margin of Twin Lakes, alti- 
tude 750 feet, Salisbury ? (G. E. N., 1910). The only New England 
station previously described is at Crystal, Aroostook County, Maine, 
where it was collected by Prof. and Mrs. M. L. Fernald.? This moss 
1 Material from this station has been supplied to Dr. Grout for distribution in N. 
Amer. Musci Pleuro. Exsic. 
2 Distributed by Grout, N. Amer. Musci Pleuro. Exsic., No. 350. 
3 See Collins, Roopora 10 : 37, 38. 1908. 
