112 SITUATION OF PLANTS. 



oiks; 16 do. of walnuts', 7 resinous trees ; 5 poplars ; 3 birches; 4 

 maples ; 3 ashes ; 2 cypruses ; 2 elms ; 2 tupelos ; 2 honey-locusts ; 

 3 magnolias ; 2 ceWw, nettle, or hockberry. 30 of the 90 rise from 

 60 to a hundred feet, 57 from 40 to 60, and many of these from 100 

 to 250 feet. 



Topography of Plants. 



The situation of plants in regard to local circumstances and the 

 effects of physical causes upon them is a subject of general interest : 

 it is called their station in contradistinction to their habitation, or geo- 

 graphical position. When found in woods, or mountains, or on the 

 sea shore of a particular country, their static is referred to, but the 

 particular country is their habitation. Seeds, as we before said, are 

 widely dispersed. Some are unproductive, being deposited in unfavor- 

 able positions, while others take root and flourish. Both soil and 

 climate are causes of the one or the other result. 



Tribes of plants originate in particular placos and increase so 

 as to drive out, or destroy, vegetables of a less vigorous growth, and 

 thus occupy large tracts of country exclusively. These are termed 

 social plants, and are thus observed in distinct tribes and of peculiar 

 species in all parts of the world ; wherever, indeed, patches of partic- 

 ular plants and of greater or less extent are- found growing wild. 

 Some of these, it is said, are constantly at war with their neighbors of 

 different species, each tribe struggling for supremacy until one or the 

 other is victorious. Some herbaceous and perennial plants are thus 

 often overpowered by a colony of shrubs of a taller and more vigorous 

 growth, and these in turn are often compelled to yield to others of still 

 greater power. Such are rarely found mixed ; they are sometimes seen 

 in patches at a respectful distance" either when the contest is going on 

 or when neither is able to prevail. Others, however, which do not in- 

 crease much by root, and which bear few seeds or are easily dispersed, 

 do not form groups, especially if they have little choice of soil. 



Singular plants of certain species occupy exclusively a large portion 

 of country. That curious vegetable, the red-snow, found among and 

 nourished by the common snows of the arctic regions, is the only plant 

 there brought to perfection. The truffle is found entirely beneath the 

 surface of the soil, where in Europe it is hunted for by truffle-dogs 

 and pigs. There are some fungi which plant themselves on the hoofs 

 and horns of dead animals, and on some dead bodies, though never on 

 living ones. Mosses and fungi grow on the dung heaps of animals. 

 A small plant is found upon and is nourished by common paper and 

 even the glass of windows, and otherthings,when exposed to dampness 

 for considerable time, produce peculiar forms. Cellars and the articles 



