Development of the Vegetation of New York State 35 
verse aspects or associations of plants in harmony with the 
soil environment. 
This fashioning of our modern, dominant, angiospermous 
plant life is a matter of so great consequence for us in getting 
the proper perspective for studies which we undertake now, 
that I shall single out several important features for special 
mention. 
Climatic Differentiation and Segregation of Floral 
Provinces. 
As late as the Miocene period of the Tertiary, warm tem- 
perate climate seems to have reached as far north as Arctic 
America. Thus Heer in Flora fossilis arctica notes the pres- 
ence of forests with pines, cypresses, birches, maples, walnuts, 
poplars, elms, oaks, lindens, willows, hazels and even Mag- 
nolia, Liriodendron and Sequoia (cf which there remain the 
“big trees”? and redwoods of California) in such far north- 
ern regions as Nova Zembla, Spitzbergen, Iceland, Green- 
land, Grinnell Land, Bank’s Land, the mouth of the Me- 
Kenzie and Alaska. But through the later Tertiary, the 
eradual cooling of the polar regions drove the strictly 
warm climate plants toward the equator, and in the 
segregation of the floristic zones the needle-leaved gymno- 
sperms came to occupy the sub-artic regions. Thus appears 
to have been formed the Arcto-Tertiary floral province of 
plant geographers. To the southward of the coniter forests 
lay a vast forest of deciduous trees embracing most of the 
familiar genera and in some cases, species, of the present. 
As a consequence of cooling of the polar regions there must 
have ensued a yearly fluctuation of temperature — warm and 
cold seasons — whose effects upon the structure and behavior 
of vegetation we know from long observation. 
Differentiation of Land Surface and of Vegetation Aspects. 
Further on in this bulletin, a good deal of space is given 
to the question of vegetation development as influenced by 
the nature of the terrain, 1. e., surface features of the land. 
