40 
Betula papyri] era var. neoalaskana 
B. glandulosa 
Geocaulon lividum 
Ribes triste 
R. hudsomanum 
R. oxyacanthoides 
R. lacustre 
Parnassia multiseta 
P. montanensis 
Mitella nuda 
Rubus acaulis 
Shepherdia canadensis 
Vaccinium Vitis-idaea var. minus 
Arctostaphylos rubra 
Pyrola asari folia 
P. secunda 
P. chlorantha 
Moneses uni flora 
Castilleja Raupii 
Linnaea borealis var. arnericana 
Peltigera aphthosa 
The general aspect of the woods does not show an abundance of second- 
ary species, since these are usually much scattered. The spruces make a 
rather close stand at the actual margins of the birch muskegs, where Ledum 
reaches its greatest abundance, but older woods are more open and the moss 
carpet is the most prominent feature of the lower strata. 
The invasion of certain types of marshy lake shores by the bog forest 
is shown in Figure 3, K. Instances of this are not regular in occurrence, and 
may be isolated on such shores as that of Moose lake. The writer can see no 
reasons for this sporadic occurrence other than the extremely gradual slope 
and poor drainage of the land and the usual presence of a typical bog forest 
immediately back of the lake margin. This is the case in every instance 
thus far examined. Another problem is that of the elevated portion of the 
muskeg forest north of Pine lake. The explanation most commonly offered 
for this phenomenon is the differential burning of peat in the fires that have 
swept the region. Such may indeed be the case, but in a country like this, 
where lake and pond levels can be demonstrated to have fluctuated so notice- 
ably in very recent post-Glacial time, much further study is necessary before 
the determining causes can be found. These elevated peat deposits are not 
uncommon, either in Wood Buffalo park or in other places in the Athabaska- 
Great Slave Lake region. 
A comprehensive study of the muskeg vegetation and peat deposits of 
the region can be said to be scarcely begun. With the limited time and 
equipment available the writer has made only a superficial record of general 
aspects, and has not attempted to make borings or to try by any other 
means to learn the earlier conditions of the muskegs. Such a study would 
reveal a great deal concerning the post-Glacial and post-lacustrine history 
of the vegetation. 
The bog forest appears to develop directly into Canada spruce wood- 
land. This may be seen near the shores of Moose lake, but it is not com- 
