40 



MODE OP GROWTH OF SEA- WEEDS. 



water only. They often assume the forms of more perfect 

 plants, presenting an appearance as of roots, stems, and leaves. 

 But these parts have not those differences of structure which are 

 characteristic of them when truly formed, and which will be 

 hereafter described ; on the contrary, they all consist of the same 



LAMINARIA 

 BACCHARINA. 



FIG. 11. 



Fucus 



VESICUIXJSUS. 



kind of simple and similar texture as that of the Confervse ; 

 the expanded leaf of a Sea- weed being composed, as it were, of 

 a number of filaments of the Confervas, laid side by side. The 

 structure of these apparently different parts being thus so nearly 

 the same, their functions or uses have an equal conformity ; f < r 

 the root-like fibres at the bottom of the stem, only serve to fix 

 the plant to the rocks or stones, to which it is its habit to attach 

 itself, instead of absorbing or sucking up nourishment as in the 

 Flowering-plants. The cause of this difference is obvious. 

 Where the whole plant is constantly immersed in the fluid, which 

 affords it the materials of its growth, no one part of it need be 

 \ specially endowed with the power : and it will be hereafter 



