167 
[Upham . 
of the Sheyenne river, North Dakota, which indicates that it was 
either introduced by the Indians or is indigenous in this region.] 
Bromus secalmus, L. ( Cheat or Chess ) , occasional in wheat-fields ; 
seldom troublesome, as its seeds are now generally separated from 
seed wheat by fanning mills. 
Agropyrum repens, Beauv. (Couch Grass, “Witch Grass”), fre- 
quent, but here rarely so plentiful in cultivated ground as to be 
troublesome. 
Hordeum jubatum, L. (Squirrel- tail Grass, “Tickle Grass”), 
common on roadsides, and on poorly cultivated, moist land. 
Concluding remarks . — In connection with my study of the gla- 
cial drift of the Red river basin and of the shore lines and delta de- 
posits of Lake Agassiz, the most interesting inquiry concerning 
the geographic range of plants there is whether we may learn from 
it somewhat of the climatic changes of the Quaternary era, with 
its Ice Age and enforced migrations of the flora and fauna of north- 
ern countries. The main outlines of these effects of the Glacial 
period have been pointed out and ably discussed by Edward Forbes, 
Asa Gray, Alfred Russel Wallace and others, who have thus ex- 
plained many peculiarities in the distribution of species, as the oc- 
currence of arctic plants on tlie^summits of mountains in temperate 
latitudes, and the identity of a considerable number of species of 
plants found in both the United States and Japan but absent from 
Europe. As geologists are lately finding valuable additions to our 
knowledge of important orographic movements of our continent 
during the Mesozoic, Tertiary and Quaternary eras from the pres- 
ent conditions of its rivers and their relations to geologic forma- 
tions, so the pages of thei geologic record receive another useful 
side-light from the range of our present species of animals and 
plants. Professor Gray well stated this bearing of botanic science 
upon geology, in the conclusion reached by his comparison of the 
floras of Japan and North America, “that the extant vegetable 
kingdom has a long and eventful history, and that the explanation 
of apparent anomalies in the geographical distribution of species 
may be found in the various and prolonged climatic or other phys- 
ical vicissitudes to which they have been subject in earlier times.” 
The general likeness of the Arctic flora all around the globe, the 
many instances of relationship and identity in the north temperate 
floras, and the increasing divergence of prevailing types as we pass 
to the equatorial regions and the southern hemisphere, indicate that 
