2G8 
GEOGRAPHICAL SITUATION. 
Tournefort, in 1700, upon one single rock in the little island of 
Amorgos, was found eighty years afterwards in the same island, 
upon the same rock, and has never been discovered in any other 
situation. Some plants appear to confine themselves within cer- 
tain longitudes, scarcely varying from the right to the left. 
The Menziesia pall folia, a species of heath, confined between 
ten and fifteen degrees of west longitude, is found in Portugal, 
Spain, and Ireland. Latitude and elevation, by reason of moun- 
tains and table lands, produce a greater variety in the appear- 
ance of vegetation than almost any other causes. 
Few plants are found to endure extreme cold. Botanists have 
estimated, that at Spitsbergen, in north latitude about 80°, there 
are but about 30 species of plants ; in Lapland, in 70°, there 
are 539 species ; at Madagascar, at the tropic of Capricorn, 
there are 5000 ; and at the equator a much greater number. 
These estimates fail very far short of the number of species 
now known, but they may give some idea of the difference in 
the vegetation of cold and warm climates. 
GEOGRAPHICAL SITUATION OF PLANTS. 
In investigating the geographical situation of the vegetable 
kingdom, we see the powerful effects of light and heat. Fee- 
ble in the polar regions, vegetation acquires strength as we ap- 
proach towards the equator, where the light of the sun is vivid, 
and its heat permanent and intense. The centre of the frigid 
zone is entirely destitute of vegetation. After passing the arc- 
tic circle, we find on the borders of the temperate zone a few 
species of plants, chiefly lichens, mosses, and ferns, also a few 
shrubs and berries. In the heat of a polar summer, the growth 
of plants is rapid ; Lapland is the only country within this zone 
where any kind of grain can be raised. 
The productions of the temperate zone gradually alter in 
character as we approach the tropics. Humboldt has divided 
the temperate zone with respect to productions, into three re- 
gions : the cold , the temperate, and warm regions. In the cold 
region, grain may be raised to advantage, and berries grow in 
abundance. In the temperate region, the wine grape, grain , 
and fruits of many kinds, are cultivated in their greatest perfec- 
tion. The warm region produces olives, figs, oranges and lem- 
ons. 
The variety of plants in the torrid zone is very great. Trees 
are more numerous in proportion to other plants, than in the 
temperate zones ; the same tribes which are there slender and 
Some have a confined locality — Few endure extreme cold. Geographi- 
cal situations of plants — Frigid zone— Temperate zone — Torrid zone. 
