HISTGRY OF PLANTS. 373 
; 348, 
Soil, Situation, cold, heat, drought, and great 
moisture, are all of powerful influence upon veges 
tation. Nobody will wonder, therefore, to find im 
every quarter of the globe, plants almost solely de- 
stined for these situations. If therefore we find the 
plants of the countries within the polar circles on 
high elevated mountains, we at once conclude that 
those plants grow in cold countries chiefly. And it 
is as little surprising to meet in America, Asia and 
Africa, i plains of the same latitude, plants of the 
same species, belonging in common to the three 
parts of our globe. 
In a geographical latitude, different parts of the 
globe may, provided that mountains or other cir- 
cumstances produce no changes in the temperature, 
produce the same plants, but in places of the same 
Jongitude different products must necessarily always 
appear. Brandenburg, the coast of Labrador, and 
Kamtschatka have nearly the same latitude, and in- 
deed have many plants in common with each other. 
Berlin, Venice, ‘Tripolis and Angola, though nearly 
of the same lone gitude, differ very van in their ve- 
getable productions. 
§ 349. 
We learned, when treating of the Physiology of 
plants, how indispensably necessary warmth was for 
vegetation. Hence it follows, that the warmer the 
climate, the greater must be the number of wild 
growing plants. The Flore of different parts of 
Aas the 
