66 College of Forestry 
ing a reservoir for the storage of heat received by day against 
the low temperatures at night.” Wilson quotes the results 
of Professor Cox’s observations on the temperature of the 
air over peat and sanded bogs respectively in which it was 
found that during August and September the night tem- 
perature at five inches above the surface averaged higher 
over sanded bog than over peat bog by about 5 degrees and the 
greatest daily difference in one instance was 19 degrees. 
Zonal Features of the New York Flora. 
I am concerned especially at this point that you should 
keep in mind the special object of the portion of the bulletin 
dealing with so-called zonal relations, which was to show that 
in the long course of time and especially since the later 
Cretaceous and early Tertiary periods of the earth’s history, 
there has been a segregation of species into categories which 
represent different degrees of climatic differentiation — in 
short that plants have kept pace with their changing environ- 
ment so far especially as the temperature factor is concerned. 
That the species which dominate New York vegetation — and 
by dominate I mean species that constitute the massive 
element in the climax forest especially, and therefore trees — 
either as now constituted or through closely related ancestral 
species, have had this climatic experience so deeply im- 
pressed that they reflect a certain fixity of temperature rela- 
tion so that whether their “zone” moves northward as im 
the Miocene and in interglacial periods or whether south- 
ward as must have happened during glacial encroachments, 
they have taken up their relatively fixed position on the 
temperature scale. So the temperature relation, whatever 
that may mean as determining plant distribution, represents 
an environmental factor or set of factors which stimulate 
a very definite response in plant behavior so far as the 
climatic conditions are concerned in which they carry out 
their life processes. J bear in mind the adaptability of 
plants, their possibilities as to acclimatization, the degree 
to which the favorable soil relation may render them inde- 
pendent of temperature barriers, and still I must look upon 
