THE VEGETABLE KINGDOM. 525 



maturity the waves carry off these reproductive germs en 

 masse, and transport them to a distance. Then when the 

 rude shocks of. the voyage have finally torn the little skiff, 

 the seeds of the sacred plant, which have remained intact 

 amid the waifs and strays, sink into the mud and water, and 

 thus fertilize the burning banks of the king of rivers. 



Even masses of ice, especially at some prehistoric epochs 

 of the globe, have played a certain part in the dispersion 

 of plants. Karl Muller thinks that the wandering blocks, 

 which the glaciers drive before them in their efforts, carry 

 certain seeds from place to place. This grand phenomenon, 

 which poured immense seas of ice over countries where now 

 a mild temperature reigns, might certainly have precipi- 

 tated some plants from the mountain tops into the depths 

 of the valleys. 



Thus at the present day we see growing in the north of 

 Germany lichens, mosses, and some woody plants, in par- 

 ticular the Swedish cornel-tree, which have evidently de- 

 scended from the mountains of Scandinavia, and have been 

 borne away by the icebergs, which, along with them, trans- 

 ported to the plains of ancient Germany the granite boul- 

 ders with which they are strewn. 



At other times the aid of another process is requisite to 

 enable icebergs to transport plants from one hemisphere to 

 another. Their floating islands, becoming detached from 

 the shore, carry away with them fragments of rock still 

 covered with animals and plants. After having been long 

 worn by the waves and currents, these islands at last light 

 upon some propitious shore, and, sinking there, deposit 

 their living population. Thus, along with the polar bears 



