408 
The Ohio Naturalist. 
[Vol. Ill, No. 6, 
doubtful if more than a very few of the phases of species distribu- 
tion can be explained from the standpoint of any one factor alone. 
It is not to be assumed that all the climatic factors of ecological 
connection have been considered in these two articles, and neither 
does it follow that any of the factors have been considered in all 
their possible phases as related to ecology, but yet enough has 
been considered to afford more or less of a basis for further work. 
It is to be regretted that the edaphic conditions, such as soil 
moisture, soil texture, etc., are not more completely worked out 
for Ohio. The}' take a very important part among the ecological 
factors, and in many cases are almost inseparably linked with 
meteorological factors. 
For a concrete instance of some of the problems of plant ecol- 
ogy, comparison may be made, for instance, between Ashtabula 
and Cincinnati, although localities differing more widely may be 
found in the State. The two stations have the same average 
range ( ioo° Fahr. ) between the average minimum and maximum 
temperatures, but Cincinnati is five degrees warmer in mean 
annual temperature, thus having decidedly an advantage as to 
the needs of many plants. The annual precipitation is the same 
in both localities, but Ashtabula has sixty inches of snow to less 
than twenty inches for Cincinnati. Now, perhaps for many 
plants the protection offered by the extra forty inches of snow at 
Ashtabula is a greater advantage than is the extra five degrees of 
temperature at Cincinnati. Again, the monthly distribution of 
the precipitation is another important factor — Cincinnati has a 
maximum of 5.69 inches in March, while Ashtabula has a maxi- 
mum of 6.95 inches in July, at about the middle of the growing 
season and just when needed for the majority of plants. Further- 
more, Cincinnati has a very drying atmosphere (low relative 
humidity) as compared with Ashtabula, but to counteract this the 
higher wind velocity at Ashtabula indicates the ability of the air 
to carry away more water. Cincinnati is farther south and would 
thus be more directly under the sun’s rays, but Ashtabula has 
less cloudy weather and so perhaps gets more sunlight than does 
Cincinnati. 
In problems like the above, where each climatic factor may 
have some certain influence upon any particular species, a debit 
and credit account might be imagined in which the factors are 
balanced, and if something is known of the requirements of the 
species, perhaps some light might be thrown upon the problems 
of distribution or the possibilities open to introduced species. 
