HOW TO KNOW THE SEAWEEDS 



135b Holdfast solid, not stupose. Fig. 174 Fucus (in part) 



Fig. 174. Fucus edentatus De 

 la Pylaie 



A fertile plant of a small 

 form of the species from 

 central Oregon showing the 

 simple, solid holdfast and 

 the swollen reproductive 

 parts (receptacles) at the 

 ends of the blades, X 0.6. 



The genus Fucus is one 

 of the most prevalent inter- 

 tidal algae in the cooler 

 waters of our coasts. From 

 central California northward 

 one or more species may be 

 found at almost any station, 

 while the same is true on 

 the Atlantic Coast to the 

 north of New Jersey. F. eden- 

 tatus occurs widely on both 

 coasts. Some species of Fu- 

 cus have inflated vesicles 

 and may be noted elsewhere 

 in this key (See Step 10.0a). 



Figure 174 I^ is to this genus that 



many of the so-called "rock 

 weeds" belong which are of 

 such economic importance 

 to the people of north At- 

 lantic shores. It is these plants which first furnished the burned ash 

 or "kelp" for the manufacture of soda used in glass and pottery mak- 

 ing in 17th century France. The value of such "rock weeds" as fer- 

 tilizer has been known and exploited for centuries, and in some areas 

 of western Europe they have been, importantly used for stock feed. 



133 



