HOW TO KNOW THE SEAWEEDS 



which is commercially employed as a thickener in soups, sauces, etc., 

 and is eaten in the raw state or after drying as a salad or vegetable 

 relish. 



Our most attractive Rhodymenia is R. pertusa (Postels & Ruprecht) 

 J. Agardh which occurs from central Oregon northward. It is broad, 

 usually simple, and has many perforations in the blade. 



Rhodymenia may often be found without cystocarps, especially 

 the smaller, dichotomous forms occurring intertidally. They have a 

 coarser, more rigid texture than Fauchea, however, and lack the very 

 broadly flabellate form. 



177a Thallus more or less regularly dichotomous. Fig. 223 



Gymnogongrus (in part) 



Figure 223 



Fig. 223. Gymnogongrus line- 

 aris (Turner) J. Agardh 



An upper portion of a ma- 

 ture plant to show the regu- 

 lar dichotomous branching, X 

 0.68. This species occurs from 

 central California to central 

 Oregon and is an example of 

 the coarse, broad forms of the 

 genus, of which G. platyphyl- 

 lus Gardner is another occur- 

 ring in CaUfornia, and G. nor- 

 vegicus (Gunner) J. Agardh in 

 New England. Beside the slen- 

 der, cylindrical G. griffithsiae 

 treated under step 22a, G. lep- 

 tophyllus J. Agardh is the only 

 slender, narrow species of our 

 territory. It is common along 

 California and Oregon. 



167 



