158 



HISTORY OF THE VEGETABLE KINGDOM. 



a general role, it may be said to depend on the 

 temperature of summer more tlian that of the 

 whole year, and is, therefore, lower in maritime 

 countries than in continental. 



Moisture and soil. Some plants require a 

 much greater proportion of moisture than others ; 

 and thus we iind some thriving on the sandy 

 rocks, while others luxuriate in the marsh, or 

 banks of the lake or river. Moisture depends 

 no less on the state of the atmosphere, and the 

 prevailing currents of winds in the district, than 

 on the nature of the soil. The quantity of mois- 

 ture influences much the vegetation of a country. 

 Marshes tend to increase rushes ; frequent rains, 

 the grasses and cryptogamic plants. 



Asp ct. Under this term are included shelter 

 from, or exposure to, particular winds, sun, light, 

 air, &c. Some plants grow best on sunny banks; 

 others scarcely exist save in the deep gloom of the 

 forest; some bear the chafings of the rudest 

 winds, by which others are immediately de- 

 stroyed. Several species in soutliern latitudes, 

 or at low elevations, will only grow in shaded 

 places ; while higher up, or fiirther north, they 

 woo the sun. The summits of hills have a more 

 rigid vegetation than vallies of an equal alti- 

 tude ; and the shores of the soa rarely show trees 

 of so vigorous growth as inland situations. A 

 small belt of trees, planted in an exposed situa- 

 tion, generally fails ; while a large compact mass 

 succeeds, though often at the expense of those 

 on the outside. 



We shall now proceed to offer a general view 

 of the distribution of vegetables over the globe. 



Scarcely fourteen hundred species of plants 

 appear to have been known and described by 

 the Greeks, Romans, and Arabians.* At pre- 

 sent, more than three thousand species are enum- 

 erated as natives of our own island; and the 

 researches of botanists in other parts of the 

 world, have extended our knowledge of the 

 vegetable kingdom to at least 50,000 species. Of 

 this vast number, comparatively few belong in- 

 discriminately to all climates and situations; 

 none, perhaps, excepting some mosses and other 

 obscure plants, which appear to require for their 

 existence only an abundance of shade and mois- 

 ture. This limitation of particular plants to 

 certain latitudes, is undoubtedly connected with 

 certain peculiarities in their internal structure; 

 though for the most part, we are unable to dis- 

 cover in what those peculiarities consist. Inde- 

 pendently, however, of the restriction thus im- 

 posed by the climate of every place on the nature 

 of its vegetable productions, each of the great 

 divisions of the earth appears to have given birth 

 to a set of plants distinct from those of other 

 parts. Thus, a large proportion of the trees and 

 plants growing wild in the western hemisphere, 

 are unlike those of the eastern hemisphere in 

 * Barton on Gcograpliical Dittiibution of Plants. 



the same latitude. The vegetable productions 

 of the Cape of Good Hope are unlike those of 

 the south of Europe, though the climate in these 

 two situations is little dissimilar. The plants 

 of the East Indian islands form another distinct 

 class ; those of Cliina and Japan another ; those 

 of New Holland again another. The little 

 island of St Helena contains a set of plants 

 peculiar to itself, not one of which is to be found 

 on the neighbouring western shore of the con- 

 tinent of Africa. The plants originally belong- 

 ing to one part of the world, when removed to 

 another enjoying a similar climate, often appear 

 to flourish as well as in their native soil. Thus 

 the potatoe, a native of South America, which 

 was brought to England by Sir Walter Raleigh, 

 in the reign of queen Elizabeth, grows as well 

 here as the turnip, the carrot, or the cabbage, 

 which are natives of Great Britain. In like 

 manner do the sugar-cane and the coffee-tree 

 flourish in the West Indies, though not originally 

 produced there, but transplanted, the sugar-cane 

 from China, the coffee-tree from Arabia. 



It will be convenient to begin our survey of 

 the vegetable kingdom from the colder regions 

 of the earth, and to proceed gradually towards 

 the warmer. Beyond the arctic circle, the 

 number of plants is extremely limited. Captain 

 Ross, speaking of a tribe of Esquimaux that he 

 met with on the shores of Baffin's Bay, says : 

 "Their knowledge of wood seemed to be limited 

 to some plant like heath, of a dwarfish growtli, 

 with stems no thicker than the finger." Ac» 

 cordingly, they knew not what to think of the 

 timber they saw on board the ship; and so little 

 notion had they of cloth, or any kind of vege- 

 table texture, that, when presented with a shirt, 

 they inquired of what animal's skin it was 

 made. On the shores of Hudson's Bay, it is 

 said that no trees are found north of latitude 

 60°. In Europe, however, vegetation extends 

 considerably further. A great part of Sweden, 

 Norway, and the north of Russia, is covered 

 with forests .of fir; and from these countries we 

 derive our best deal tiral)er. The yellow deal, 

 which is most valued, is the wood of the silver 

 fir; white deal of the spruce fir. 



In no part of the 

 world has the distribu- 

 tion of plants been more 

 carefully observed than 

 in Norway and Lapland. 

 The trees which are 

 there found to approach 

 nearest the limits of 

 perpetual snow are the 

 dwarf birch and dwarf 

 willow, if they can be 

 projierly denominated 

 trees; the dwarf birth seldom exceeding two or 

 three feet in height, jind the dwurf willow being 



73. 



Dwarf Willow. 1 



