CRYPTOGAMS 



177 



BROWN ALGJE 



428. The Brown Algge (Fig. 291) are almost exclusively- 

 salt-water plants. They are in most cases attached. In size 

 they range from microscopic, unicellular forms, through 

 the fine filamentous species (Fig. 291, D), to thalloid 

 forms of immense length. " Of these, Macrocystis pyrifera 



291. Brown Algae: A, the Sea Colander (much reduced) ; B, Larainaria (much 

 reduced) ; C, the Gulf Weed with floats (a) ; D, Ectocarpus (magni- 

 fied), s being sporangia. 



is noted for its gigantic size : rising obliquely upward to 

 the surface of the water from the sloping sides of eleva- 

 tions in the ocean bed, its floating thallus has a length of 

 600 to 900 feet. The stalk below is naked, but at the 

 surface, where it streams out horizontally, it bears many 

 long pendent segments, each provided at the base with a 



OUT. OF EOT. 12 



