NATURAL HISTORY OF PLANTS. 



whole of theJAfrican surface consists, increases the heat. The region^ 

 about the North Pole are much more temperate than those at the 

 South Pole. Tierra del Fuego lies under the 55th degree of south- 

 ern latitude, and has a much more inclement sky than prevails in 

 Europe under the fjQth. Mountains that raise themselves high 

 above the cloudsj have, in all latitudes, perennial snow upon their 

 extreme summits. Cook found such a mountain in the Sandwich 

 islands; and in America, the celebrated Andes have their tops 

 covered with perpetual ice under the tropics and the line, while a 

 constant summer is felt in the vallies. 



Situation, heat and cold, wet and dry soils, have great influence 

 on the whole of vegetation. It is not therefore surprising to find 

 in every region of the globe, plants adapted to each particular situ- 

 ation. Accordingly, when we meet on the tops of high mountains 

 the plants'of Polar regions, we infer that these plants were destined 

 for cold climates : nor ought we to wonder that, under the same 

 latitudes in Asia, Africa, and America, we find, on similar soils, 

 plants which are native in all these quarters of the globe. 



In one geographical latitude, if no mountains or other circum- 

 stances change the temperature, the same plants are found to 

 grow ; but places in the same longitude, must always exhibit vari- 

 ous productions of the vegetable kingdom. The Mark of Bran- 

 denburgh, the coasts of Labrador and Kamtschatka, lie nearly 

 under the same latitude, and produce therefore many plants in 

 common. Berlin, Venice, Tripoli, and Angola, are nearly in the 

 same longitude ; but their plants are very different. 



It is well known that warmth is necessary to vegetation : hence 

 it naturally follows, that in the warmer climates, the number of 

 native plants will be most considerable. The Floras, made by 

 botanists in different countries, shew, that vegetation increases ac- 

 cording to the degree of heat. In Southern Georgia*, by the best 

 accounts, there are only two native plants : in Spitzbergen, there 

 are 30 : in Lapland 534: in Iceland, 553: in Sweden, 1299: in 

 the Mark of Brandenburgh, 2000: in Piedmont, 2800: on the 



* An island of considerable extent discovered by La Roche, in 1675, and 

 explored by Captain Cook in 1775, who named it Georgia. It is a land of ice, 

 aid snow, with few vegetables but lichens, Editor, 



