HOW TO KNOW THE SEAWEEDS 

 126b Thallus branched above the base 131 



127a Blades with a single median stripe which may be up to 4 cm. 

 broad 128 



127b Blades with more veins than a single midrib 129 



128a Blade perforated. Fig. 166 Agarum cribrosum 



Figure 166 



Fig. 166. Agarum cnbrosum (Martens) Bory 



The lower part of a small plant showing the holdfast, midrib, and 

 perforations of the blade, X 0.5. This is a cold water plant occurring 

 in northern New England and also in the Puget Sound region of our 

 north Pacific Coast. It is normally found in deep water, but dwarfed 

 examples may be encountered intertidally. Another species, A. fim- 

 briatum Harvey, with fewer and less conspicuous perforations and 

 flattened rather than cylindrical stipe occurs abundantly in the lower 

 Puget Sound and sparingly in deep water along the southern CaU- 

 fomia coast. 



126 



