232 ALG/E. CHAP. IV. 



CHAPTER IV. 



ALGJE. 



Descrip- THE term Algae, which is of Latin derivation, 

 habitats, seems originally to have denoted any sort of plant 

 or herb growing in sea-water. But among modern 

 botanists it has a much more extensive significa- 

 tion, including not merely marine and many other 

 immersed plants, but also a great variety of plants 

 that are not even aquatics, agreeing however in the 

 common character of having their herbage frondose, 

 or but rarely admitting of the distinction of root, 

 stem, and leaf, and their fructification imbedded, 

 either in the substance of the frond itself, or in 

 some peculiar and generally sessile receptacle. 

 The most common distribution of the tribe of the 

 Algae is that by which they are divided into the 

 six following genera : Lichen, Tremella, Fucus, 

 Ulva, Conferva, Byssus. But future investigators 

 will probably find room for considerable alteration . 



SECTION I. 

 Conservative Organs. 



Modifica- The Root. The Algae are but seldom found to 

 exhibit any evident traces of a distinct and decided 

 root, though they are often attached to the sub- 



