358 Part IV. Chapter 1. 
of the northern arm of the lake grow Menyanthes trifoliata, Parnassia palustris, 
Calla palustris, with sedges and grasses. In a small pond on one of. the 
Simpson islands is found a colony of Nymphaea ( Castalia) tetragona (growing 
only in a few other stations in North America). "The southern shore of Great 
Bear Lake is characterized by the presence of Salir alaxensis, 5. glaucops; 
S. reticulata, Vaccinium uliginosum and Myrıca gale. 
Bog Formation. The bog plants of this district are. the common Rubus 
chamaemorus, Vaccinium canadense, V. vitis-idaca, Ledum latifolium, Betula 
pumila, and several species of Salır. 
Back of Fort Norman the muskegs are filled by shrubby growth of Iyonia (Chamaedaphne) 
calyculata, Andromeda polifolia, Ledum latifolium and L. palustre, Vaccinium uliginosum, wbile 
in other muskegs of the region occur in addition Salix myrtilloides, Rubus chamaemorus, Em- 
petrum nigrum, Kalmia glauca. | 
Prairie and River Bank Formation. Along the Peace River in the south- 
west of this district the slopes of the hills are very warm, being inclined toward 
the sun at a considerable angle and on these the greater number of prairie 
species by whose presence this district separates itself from those in the east 
are found, viz., Opuntia missouriensis and others. The common Rocky mountain 
pine P. Murrayana enters the district from the south where it meets from 
the east Pinus Banksiana and Larir americana, which forms the so called 
tamarack swamps. 
Shepherdia canadensis occurs on rocky declivities and boulder strewn banks, 
while Elaeagnus argentea occupies sandy situations. Salıxr candida, Lactuca 
pulchella, Heuchera hispida inhabit damp stream banks and Geum triflorum 
with Woodsia ilvensis on rocks. 
All the country south of Great Bear Lake almost as far east as the 
Coppermine River is fairly well wooded and abounds in lakes'). North of the 
lakes the tundra prevails. 
D. Alaska District. 
The only change that takes place in the sub-arctic forest when the northern 
Rocky Mountains are reached in Alaska, north of 53°, is the substitution of 
Pinus Murrayana (= P. contorta var. Murrayana) for P. Banksiana and Abies 
subalpina (= A. lasiocarpa) for A. balsamca which was left far to the east; 
otherwise the same forest extends from Labrador to the tundra of Alaska and 
to the Pacific coast in the neighborhood of Cook Inlet. The separation of 
the coast Pacific flora from that of the interior with which we are here con- 
cerned, is in general complete. 
Sub-arctic Coniferous Forest Formation. The character of the interior of 
Alaska is far from well known. We known that Picea alba is here the most 
important species (Picea alba-Facies) and it attains a considerable size north 
ı) Bert, J. Macınrosn: Explorations in the Great Bear Lake Region. Geographical Journal 
XVIH: 258. September 1901. 
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