Development of the Vegetation of New York State 43 
dacks and 150 days in the St. Lawrence valley somewhat 
farther north. 
4. The highly differentiated terrain or substratum for 
plant growth which New York State presents —a terrain 
which as we learned was in a great measure prepared by 
glacial action — is the sort of environment to call forth the 
widest range of vegetation aspects, a condition which might 
be characterized as a mosaic of plant associations — water 
vegetation, marsh-meadow and swamp forest, climax forest of 
varying composition according to zonal boundaries, and 
finally even a bit of arctic vegetation (as on the summit of 
Mt. Marcy). 
5. The presence of so vast and varied a population of 
animals and plants crowded into an area lke that of New 
York State becomes itself one of the most determining or 
most powerful groups of environmental factors. These 
interrelations of organisms are too complex for presenta- 
tion here even if one could successfully analyze them, but 
one need only »ention the native mammal population — 
deer, beaver, porcupine and the vast numbers of small 
rodents — and their habits with respect to plant life; the 
bird population especially as related to seed distribution ; 
the insect fauna particularly as regards flower pollination 
and preying upon foliage; wood-boring and bark beetles, 
ete. ; the crowding of plant species into compact formation as 
in a high forest with resulting adjustments in form, shade 
tolerance, etc.; the forest floor species; the forest soil fungi 
and bacteria and their relation to a sanitary soil; the wood 
destroying fungi, parasitic fungi, symbiotic relations, and 
so on. 
The Content of the New York State Flora. 
It may seem a bit curious in view of the advanced state 
of botanical knowledge, of the great activity in botanical! 
investigation, of the extent to which botanical study is car- 
ried on in high schools and colleges, and particularly in view 
of the extent to which botanical knowledge is applied in 
exploiting and protecting crop production and forestry, that 
we should be so far from knowing what species of plants 
