80 



PLANT MORPHOLOGY 



Fig. 68. A sea palm {Postelsia palmaefonnis) growing on a rock exposed at low tide, about 

 one-quarter natural size. 



6. Fucales 



The Fucales, commonly known as rockweeds, are a highly specialized 

 order of brown algae standing apart from the others. They are widely 

 distributed throughout tropical and temperate regions, most of them 

 growing along rocky seacoasts in the intertidal zone. They comprise 32 

 genera and 325 species, representative forms being Fucus, Pelvetia, 

 Ascophyllum, and Sargassum. 



Fucus. Fucus is widely distributed in cool waters, being represented 

 along both the eastern and western coasts of North America. The 

 thallus, rarely exceeding a meter in length, is coarsely ribbon-like and 



