Vegetable Productions of' the HudsorCs Bay Countries. 
trading route ; but several, even of these, may nevertheless be 
indigenous. Blitum capitatum.^ Veronica peregrina, Lycopus 
Virginicus, Hordeum juhatum, Myosotis lappula^ Rumex acutus^ 
Cerastium viscosum, Spergula nodosa, Euphrasia officinalis, 
Lepiditim ruder ale, Atriplex , Urtica gracilis. 
The only mode in which the arts and customs of the natives 
alfect the vegetable kingdom, is by their setting fire, either ac- 
cidentally or intentionally, to the forests. These fires, when 
they occur during summer in the woody district, spread rapidly 
through the dry moss, consuming the soil down to the rocks, 
and are only extinguished by heavy showers of rain. Several 
years elapse before any thing grows in the district thus laid 
waste. The blackened and branchless trunks of the trees are 
in a season or two stripped of their bark and bleached, if not 
sooner thrown down by the wind. The surface of the ground 
next acquires a little verdure from the Funaria hygrometrica, 
Bryum pyriforme, Didymodon pur pur cum, Marchantia poly- 
morpha and conica, and some other Musci and Hepaticce. By 
and by other vegetables take root, and in process of time the 
site of a pine-forest is occupied by dense thickets of slender as- 
pens (Popidus trepida ). The growth of this tree, instead of a 
renewal of the pine-forest, may be attributed either to a change 
in the nature of the soil, perhaps by the introduction of a greater 
quantity of alkaline matter, — to its winged seeds favouring its 
dispersion, — or to both causes conjoined. The ashes of the 
poplar yield much more alkali than those of any of the pines do. 
Fires frequently spread amongst the dry grass in the plains 
of Carlton House ; but their principal effect there seems to be the 
production of finer pasture in the following season. They do 
not seem in general severe enough to destroy the roots of the 
grass, or to burn the soil. The migrations of the herds of the 
bison or buffalo, are much influenced by the extent and direction 
of these fires. 
