
1128 The American Naturalist. [December, 
BOTANY, 
The Trees and Shrubs of the Basin of the Red River 
of the North.—In a recent paper on the ‘‘ Geographic Limits of 
Species of Plants in the Basin of the Red River of the North’?! Mr. 
Warren Upham discusses a number of interesting problems in geo- 
graphical botany. This basin lies between 45° and 52° north lati- 
tude, and 95° and 106° west longitude. At its lowest point at Lake 
Winnipeg its elevation above sea-level is 710 feet, and from this it 
rises to 2,700 feet’ in Northwestern Manitoba and Eastern Dakota. 
The temperature of this valley ranges from go° Fahrenheit to —30°, or 
even —40°, e annual rainfall is from 20 to 30 inches. 
The boundary between forest and prairie is traced as follows: 
Beginning near the junction of the north and south forks of the 
Saskatchewan River (about lat. 53° north, long. 105° west), and run- 
ning southeasterly to Duck Mountain, the south end of Lake Mani- 
toba and Lake Winnipeg, thence southerly from fifteen to fifty miles 
“east of the Red River to Central Minnesota, where it bears eastward, 
passing out of the Red River basin. West of this line the region is 
chiefly grassland, while east of it the surface is almost wholly tim- 
‘ Groves of a few acres, or sometimes a hundred acres or 
more, occur here and there upon the prairie region beside lakes, and a 
narrow line of timber usually borders the streams, as the Red River 
and its principal tributaries; but many lakes and creeks, and even 
portions of the course of large streams, have neither bush nor tree in 
sight, and occasionally none is visible in a view which ranges from five 
to ten miles in all directions.’’ 
Mr. Upham discusses the trees and shrubs of the region as follows: 
‘‘ Many species of trees, which together constitute a large part of the 
eastern forests, extend to the Red River basin, reaching there the 
western or northwestern boundary of their range. Among these are 
the basswood, sugar maple, river maple, and red maple, the three 
species of white, red, and black ash, the red or slippery elm, and the 
rock or cork elm, the butternut, the white, bur, and black oaks, iron- 
wood (Ostrya virginica Willd.), the American hornbeam (Carpinus 
caroliniana Walt.), the yellow birch, the large-toothed poplar, white 
and red pine, arbor vite, and the red cedar or savin. A few species 
of far northern range find in this district their southern or south 
1 Proc. Boston Society of Natural History, Vol. XXV., p. 140. 





