KELPS 201 



Pacific coasts are the Sea Girdle (Cymatherc) with a 

 narrow beautifully ribbed "leaf"; the Sea Tree (Lessonia) 

 with a stout branching stem bearing many small leaves; 

 the Sea Palm (Postelsia) with an unbranched stem bearing 

 a tuft of leaves at the top; the Bladder Kelp (Nereocystis) 

 with a long, cord-like stem, often 10 to 15 meters long and 

 bearing an air bladder at the top, to which is attached a 

 tuft of large leaves; the Giant Kelp (Macrocystis) with a 

 long, slender, cord-like stem, sometimes 50 to 75 meters 

 long and bearing a row of large leaves toward its extrem- 

 ity, each with a basal air bladder; the Leafy Kelp (Egre- 

 gia) with a flat stem which bears innumerable lateral leaf- 

 lets and air bladders. 



307. The highest of the Brown Seaweeds are the Rock- 

 weeds and Gulfweeds (Fucales) in which the plant body is 

 of medium size (usually from a decimeter 

 to a meter in length), rooted below, and 

 massive and branching above. Their 

 tissues, too, show a considerable differ- 

 entiation; the cells are arranged in cell- 

 masses, and these are differentiated into ^ „., -^ 



' . . Fig. 87. — Fuciis. 



several varieties of parenchyma, and other 

 tissues approaching, in some instances, to the condition 

 which prevails in higher plants. Some species develop 

 air bladders in their tissues. 



308. With the foregoing there is found a marked differ- 

 entiation of portions of the plant body into general re- 

 productive organs, analogous to the floral branches of 

 higher plants. The sexual organs are developed upon 

 modified branches, which differ more or less in shape and 

 appearance from those destitute of such organs. 



309. In all Rockweeds the asexual reproduction 

 ("propagation") has been suppressed, the emphasis being 

 placed upon the sexual reproduction ("generation"). 



