THE GEOGRAPHICAL DISTRIBUTION OF NORTH DAKOTA PLANTS 235 
Canadian Zone Species 
Upham (12) has given a list of about 75 northern species which reach 
their southern hmit in the basin of the valley of the Red River of the North, 
but very few of these are known in North Dakota. The few Canadian 
Fig. I. Sketch map of North Dakota and adjoining states showing localities mentioned 
and life-zone boundaries as given by United States Biological Survey.^ H — 1 — h lower limit 
of Canadian Zone; — upper limit of Upper Austral Zone (Transition Zone between); . . . 
southern limit of glaciated area in North Dakota, 
Zone plants which occur in the state are found in the Turtle Mountains 
and Pembina Mountains (as far south as Milton), these being outlying 
points cut ofif from the body of the zone by a distance of 100 miles or more. 
The following species may be mentioned : 
Anemone Hudsoniana Oxytropis deflexus 
Corylus rostrata Mitella nuda 
Geranium Bicknellii Rihes triste 
Polygala Senega Circaea alpina 
Pyrola asarifolia Lepargyrea canadensis 
Arctostaphylos Uva-ursi Cornus canadensis 
^According to the fourth provisional map (1910). Mr. Vernon Bailey, who has read 
the manuscript of this paper, writes that in a report on the mammals of North Dakota 
which he has about completed, he has extended the Upper Austral limit to the mouth of 
the Cannon Ball River and a little way up that river; also a little farther in the western 
valleys. 
