89 
ANNOTATED LIST OF FLOWERING PLANTS AND FERNS 
So far as is known at present the Wood Buffalo Park area was entirely 
denuded of its flora during the Pleistocene glaciation, so that the present 
cover has migrated into the region and established itself since that time. 1 
This new flora consists of elements from widely separated regions and may 
be roughly separated into two groups of species. The first consists of the 
wide-ranging plants known throughout the Canadian forest; the second 
is made up of species from the mountains and plains of the western and 
interior parts of the continent. 
The larger part of the flora is made up of species in the first of these 
groups. The major trees are Picea glauca, P. mariana , Pinus Banksiana, 
Populus tremuloides, P. tacamahacca, and Betula papyri] era var. neoalask- 
ana. With the exception of Pinus Banksiana, which reaches its greatest 
northwestward extension in the Athabaska-Great Slave Lake region, these 
species range from Newfoundland to Alaska. Among the herbs, Car ex 
tenuiflora and Glyceria grandis illustrate the same wide range. The chief 
variation in this group is a sub-arctic tendency in exposed situations such 
as high, rocky, and sandy hills or cold bogs. 
The mountain and plain elements may be divided into three groups. 
The first consists of species widely distributed from western Yukon or 
Alaska southward in the Cordilleran region and eastward in the Great 
Plains. It is represented in Wood Buffalo park by such plants as Bromus 
Pumpellianus, Stipa. comata, Elymvs innovatus, Carex obtusala, C. Rossvi, 
Salix lasiandra, Trientalis europaea var. arctica, and many others. A 
second group is made up of plants from more southern mountain and 
interior plain districts. It may be illustrated by Poa arida, Spartina 
gracilis, Fluminia festucacea, Agropyron Smithi var. molle, and Salix 
lutea. The third group is of species from the western mountains that also 
range eastward to Ontario and New York, and is illustrated by Carex 
Richardsonii and C. trichocarpa var. aristata. 
In addition to these major elements, certain marginal floras should be 
mentioned. A distinguishing feature of nearly all of the heavily timbered 
areas is the absence of many species that are usually found in the richer 
parts of the Canadian forest (53). The causes of this are thought to be 
the relatively short time available since much of the country was drained 
of its post-Glacial lakes, and the retarding action of the severe climate 
upon the development of soils. This rare or entirely absent element in the 
flora includes such species as Abies balsamea, Cinna latifolia , Circaea 
alpina, Thelypteris Dryopteris , T. spinulosa, Streptopus roseus, Habenaria 
orbiculata, and many others. It is of considerable interest that the first 
three of these have now been found in the upper delta of Athabaska river, 
which appears to be at the present northern margin of their range. A 
second marginal element is found at the eastern edge of the Caribou Moun- 
tain plateau, and includes species of the Cordilleran region such as Pinus 
contorta var. latifolia, Arctagrostis arundinacea, Carex loliacea, and 
Thalictrum sparsiflorum. 
i See also the writer’s treatment of this matter in " The Distribution and Affinities of the Vegetation 
of the Athabasca -Great Slave Lake Region; Rhodora xxxii, p. 198 (1930). 
