Wheeler: THE FLORA OF THE RED RIVER VALLEY. 599 
EXPLANATION OF PLATE XXXIV. 
General view of prairie near Shirley, Minn. This is the charac- 
teristic aspect of mesophytic prairie in the Red River valley. The 
shrubs are Sadzx humilis, for the most part. The herbs in the fore- 
ground are Asters. The view shows a minor tension line in which 
Juncus dudleyz is an abundant plant. On the right a growth of Poly- 
gonum intermixed with Andropogon is seen. The view gives an idea 
of the variety of the prairie vegetation. 
PLATE XOX XV’. 
An island of Hlordeum surrounded by a border zone of Sax inter- 
mingled with Symphoricarpos and Solidago. Such circular patches of 
squirrel-tail grass marking slight depressions in the prairie are not un- 
common and often reach a considerable size,even covering several acres. 
Pram XOXOevil: 
Prairie near Gentilly, Minn. In the background is seen the shrubby 
and scanty arboreal vegetation along the Red Lake river. In the 
middle distance a minor tension line of Zordeum is apparent extending, 
in this case, several miles along the river. In the foreground WVadalus 
racemosus, a characteristic wand plant of the region, is seen forming 
an almost circular patch in the general grass vegetation. 
12 yey Naeis OOO WANA 
Gopher mound with characteristic vegetation. These mounds made 
by Geomys bursartus are abundant on the prairie throughout the dis- 
trict. Somewhat more xerophytic plants inhabit them than are found 
upon the level prairie where they occur. Upon this particular mound 
hazel-brush, Artemzsta, Bouteloua, Solidago rigida and other semi- 
xerophytic or strongly xerophytic plants have secured a foothold. 
lean DOOWAUNE 
A growth of silver-berry—Zleagnus argentea. This plant is 
abundant throughout the district studied, in dry declivities or on slopes 
of the rolling prairie. It is also abundant in pastures along the Red 
Lake river. 
PLATE XXXIX. 
View of the margin of a grass meadow in the poplar scrub near 
Maple lake showing three stands of Sal¢x lacéda, a common plant of 
the tension zone between the meadow and the scrub. 
1a oad Be 
View of xerophilous vegetation on knolls along a coulee cut in the 
raised beach of the extinct Lake Agassiz near Fertile, Minn. The 
