20 
seasons. Much of the Salt Plain has barren or semi-barren flats which are 
the bottoms of shallow ponds in the spring and early summer. The water 
in these ponds is somewhat saline due to the outwash from the salt springs 
of the region, so that vegetation on the flats has a distinctly halophytic 
character. Glasswort S alicornia europaea, sea milkwort Glaux maritima , 
and various other salt marsh plants are common in the more saline areas. 
The baltic. rush Juncus balticus, and the blue- joint grass Calamagrostis 
inexpansa var. brevior, cover large areas of semi-saline land. The widest 
expanse of semi-open prairies is on the Salt Plains. Small local areas are 
to be found in certain types of sink-holes. 
The flood-plain and delta lands of the lower Peace and Athabaska 
rivers and the Lake Claire-Lake Mamawi basin have extensive marshes 
ranging from very wet or aquatic shore associations to grasslands. The 
sloughs and wet meadows are separated by natural levees and other 
alluvial deposits formed by the meandering channels of the rivers. These 
slightly higher, better-drained soils have willow clumps or timber on them. 
Two of the most widespread species are the blue- joint grass Calamagrostis 
canadensis , and the meadow sedge Carex trichocarpa var. aristata . These 
form extensive “ hay-meadow r s ,J throughout the lowlands. Minor flood- 
plain areas are to be found on the lesser streams that drain the uplands, 
such as Salt and Little Buffalo rivers. The vegetation on these is similar 
to that of the main lowlands. 
From the above brief discussion it is evident that the most extensive 
timbered areas are on the uplands that have been exposed since the lowering 
of the post-Glacial lake that stood at about the 1,100-foot level. They do 
not cover all of this upland, but are broken by the wide muskeg district 
of the Moose Lake-Bog Lake basin and by the semi-open prairies on the 
clay soils that lie northwest of Pine lake and at the base of Caribou Moun- 
tain plateau. The prairies have their widest spread in the country south 
and west of Fort Smith, which was formerly under the lake that stood at 
about the 800-foot level. The slough and timber vegetation of the lowdands 
is growing mostly on the alluvial deposits that have been formed in the last 
of the post-Glacial lakes, which stood only a few feet above the present 
water-level of lake Athabaska. 
The ensiling, more or less detailed, discussion will follow the general 
outline given in the preceding paragraph. 
THE UPLAND FORESTS 
The richest forests in Wood Buffalo park are of Canada spruce Picea 
glauca . They have a comparatively small flora, with very little under- 
growth, and the mat of mosses that forms most of the ground cover is at 
most only 4 to 6 inches deep, over a leaf mould seldom exceeding 4 inches in 
thickness. 
Primary spp.: Picea glauca 
Salix Bebbiana 
Hypnum Crista-castrensis 1 
H. Schreberi 
1 The writer is indebted to Prof. J. Franklin Collins of Brown University for determinations of 
the mosses listed. 
