. NATURAL HISTORY OF PLANTS. QQ 



sometimes thrown oil the shores of Norway. Were the climate of 

 that country fit for such plants, cocoa nuts, and other plants of the 

 torrid zone, would be planted and prosper. The seeds of the ser- 

 vice tree are carried to remote places by our rivers. Many German 

 plants have been observed on the coasts of Sweden, many Spanish 

 aud French on the shores of Britain, many African and Asiatic on 

 the shores of Italy. 



The wind carries the seeds that are furnished with down, with 

 wings or membranaceous rims, as also those that have swollen cap- 

 sules, to places convenient for their germination. By this means 

 too, some plants that have light seeds are scattered in the tract of 

 the prevailing winds, and carried to places they would not other- 

 wise have reached. Tbe wind carries the winged seeds of the 

 birch, (Betula alba), to the tops of towers and high rocks, where 

 they germinate. The birch it likewise, by reason of its light seeds, 

 dispersed over northern Asia, whither the heavy acorns of the oak 

 (Qiiercus Robur) cannot follow them. 



Many seed capsules and fruits burst with an elastic force, and 

 scatter their seeds round about, while others are obliged to remain 

 iu the places where they are produced, particularly such as ripen 

 under-ground. The pistillum of some plants, after flowering, turns 

 down, and pushes itself into the earth, where the seeds couuj to 

 perfection. Examples of this are found in Arachis hypogcea. Gly- 

 cine subterranea, Trifolium subterraneun, Lathy rus amphicur- 

 pos, Vicia subterranea, Cyclamen, &c. Berries, and all succulent 

 fruits, cannot disperse themselves : they fall to the ground, and 

 their soft skins nourish the young plant. Many birds, and other 

 animals, feed on these ; they carry them away, and having eaten the 

 succulent part, let the seeds drop, or the seeds pass uninjured 

 through their intestinal canal, and are thus propagated. In this way 

 the Misletoe, (Viscuin albu?n), is sown by a bird, the Missel-thrush, 

 (Turdus viscivorus), and thus also the Juniper, (Juniperis com,' 

 munis). 



But man himself has done more for the dispersion of plants, 

 than winds, or seas, or rivers, or animals. He whom all nature 

 obeys, who changes the wilderness into fertile fields, who lays waste 

 whole countries, and again restores them, has, in various ways, pro- 

 moted the dispersion of plants. 



The wars which nations wage with one another ; the migrations 



