7S Estdblisliment of Vegetation at the surface of the Globe. 



upon the hardest bodies, upon stones and rocks, to which they 

 adhere by a base of great tenacity, or rather are cramped by 

 means of a sort of branched claw, very different from a root, 

 although having its appearance. These claws are not destined 

 to draw from a soil which they cannot penetrate, alimentary 

 juices which are to be carried to the upper parts of these vege- 

 tables ; for these parts, being entirely immersed in the same me- 

 dium, equally absorb, by the whole of their surface, the princi- 

 ples of their nutrition, and we have not as yet been able to dis- 

 cover the ascent of any liquid, such as sap, &c. Marine plants 

 have, besides a foliage which is plane or divided into filaments, of 

 a phant texture, a coriaceous or membranaceous structure, sus- 

 ceptible of accommodating itself to all the motions of the water 

 in which it is immersed, without receiving any injury. 



Although their mode of fructification is still little known, it 

 appears that their seeds, or what they have in place of them, are 

 very glutinous ; that they attach themselves indifferently to all 

 solid bodies, and cover the rocks with a vegetation equally 

 abundant, and not less agreeable than that of the swards which 

 carpet our mountains. It is true they do not expand brilliant 

 coroUae, nor fill the air with their perfumes, but they often pre- 

 sent, in the form, variety and mixture of the colours of their 

 foliage, an aspect not less seducing. 



It would be difficult to say what are the circumstances fa- 

 vourable or hurtful to their multiplication ; but if we examine 

 the rocks which it is permitted us to approach, we shall find 

 them covered with a rich vegetation. It is to be supposed that 

 these plants, although placed in the same general medium, are, 

 equally with terrestrial plants, subjected to the influence of lo- 

 calities, depths and temperature, since there are some which on- 

 ly shew themselves in certain seas, which are met with, for in- 

 stance in the Atlantic, while they are not to be seen in the Medi- 

 terranean, which occur in the Indian Ocean, while they are de- 

 nied to the frozen seas of the north, &c. Others grow at such 

 depths that we are only acquainted with them by means of their 

 fragments. 



I shall not follow further in her great works. Nature inces- 

 santly occupied in laying everywhere the foundations of vegeta- 

 tion. What I have said will suffice to present an idea of all the 



