Marine Groves and Gardens 119 



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very structure of its surface, but in the succession of 

 living forms which have inhabited it. Yet the simplest 

 plants have outlived them all. Many there are that 

 have persisted unaltered throughout the countless ages 

 that saw the appearance and disappearance of mighty 

 hosts of higher forms. Ancient as is animal life, the 

 lowly plants probably antedate them by a period so 

 great that in comparison the existence of the former 

 would seem to be but of a day. 



It is, therefore, with peculiar interest that we turn 

 to the vegetation in the sea, for, as was pointed out 

 in a previous chapter, this region was the probable 

 source of all life. This vegetation, with very few 

 exceptions, is comprised entirely of the lowest forms 

 of plant life. Now this will appear strange to the 

 reader whose limited acquaintance with the seaweeds 

 has led him to look upon their varied and ofttimes 

 beautifully branched fronds as structural counterparts 

 of land plants. As a matter of fact, however, they 

 have nothing in common with the higher terrestrial 

 types. Seaweeds all belong to that division of plants 

 termed thallophytes. All thallophytes living in water 

 and obtaining their nourishment directly therefrom are 

 further distinguished by the name alg^e. It is for the 

 reason that they are composed of one class of cells that 

 algae are the lowest and simplest of plants. In this 

 respect, it must be borne in mind, the familiar flowering 

 plants are totally different. The groups of cells which 

 constitute the stem and the leaf and various other parts 

 of the plant are vastly unlike in their character and 

 function. In the higher forms of marine algae, the 

 vegetative body is called the frond. The disk or ex- 



