He further found that there was an element which he termed boreal in a more intense degree, which amounted to about a fifteenth of the whole flora.
Or Boreal branch of the yellow or Mongolic race.
North-western corner of the state, which lies in the Boreal zone.
In the forest regions north of the lakes the vegetation on the shores of Lake Erie requires a high winter temperature, while the east and north shores of Lake Superior have a boreal vegetation that shows the summer temperature of this enormous water-stretch to be quite low.
In the Old World the boreal zone is almost sharply cut off and afforded no means of escape for the Miocene vegetation when the climate became more severe.
The Transition zone, in which the extreme southern limit of several boreal species overlaps the extreme northern.
On the whole, we may say that the arctic and boreal faunas of Europe extend over Siberia, with a few additional species in the Ural and Baraba region - a number of new species also appearing in East Siberia, some spreading along the high plateau and others along the lower plateau from the steppes of the Gobi.
There are firs and spruces on the mountains, characteristic of the Boreal zone; pines characteristic of the Transition zone; pinon juniper, greasewood and the universally conspicuous sage-brush, characteristic of the Upper Sonoran zone.
With this animal diet everywhere vegetable substances were mixed, even in the boreal regions.
The boreal fauna is, of course, much more abundant; but here also the great bulk of the species, both mammals and birds, are common to Europe and Asia.