422 CAUSES LIMITING PROPAGATION. CHAP. X. 



SECTION I. 

 Soils. 



ALL plants will not vegetate in all soils, many 

 of them even affect a peculiar soil ; and where that 

 soil is not to be found, they will not grow. It 

 should be observed, however, that in this view of 

 the subject the term soil is used in a very extensive 

 acceptation, as signifying not only the various sorts 

 of mould which copstitute the surface of the earth, 

 but every substance whatever on which plants are 

 found to vegetate, or from which they derive their 

 nourishment. The most general division of soils 

 in this acceptation of the term is that of aquatic, 

 terrestrial, and vegetable soils ; corresponding to the 

 division of aquatic, terrestrial, and parasitical plants, 



SUBSECTION I. 



Aquatic Soils. Aquatic soils are such as are 



either wholly or partially inundated with water, 



and are fitted to produce such plants only as are 



denominated aquatics. Of aquatics there are several 



subdivisions according to the particular situations 



they affect, or the degree of immersion they require. 



Producing One of the principal subdivisions of aquatics is 



plants? tnat f marme plants such as the Fuci and many of 



the Ulvce, which are very plentiful in the seas that 



