It has floras of the plains, the hills and the mountains; an alpine flora, and an arctic flora; a flora of marshes, and a flora of steppes; floras peculiar to the clay, the chalk, the sandstone and the slate formations.
The central region is a transition ground where these floras find representation generally in deteriorated and dwarfed species.
A detailed examination of mountain floras shows that a large local element is present in each besides the arctic. The one is in tact the result of similar physical conditions to that which has produced the other.
It took place southwards, for the arctic flora is remarkably uniform, and, as Chodat points out, it shows no evidence of having been recruited from the several mountain floras.
At the same time the then existing alpine floras descended to lower levels, though we may agree with Ball that they did not necessarily become extinct at higher ones as long as any land-surface remained uncovered by ice.