HOW TO KNOW THE SEAWEEDS 



129a Thallus simple, or lobed and deeply divided or lacerated; hold- 

 fast not dichotomous 130 



129b Thallus consisting of several strap-shaped blades from a dicho- 

 tomously branched holdfast. Fig. 168. .Dic/yoneurum californicum 



Fig. 168. Dicfyoneurum californicum Ru- 

 precht 



Basal part of a plant to show the 

 dichotomous holdfast and the reticulate 

 venation of the Ugulate blades, X 0.5. 



Frequent on surfy rocks along the 

 Pacific Coast from central CaHfornia 

 northward. 



Figure 168 



130a Blades reddish, with a network of veins. Fig. 169 



Polyneura laiissima 



Fig. 169. Poiyneura latissima 

 (Harvey) Kvlin 



A lower portion of a plant 

 showing the small holdfast, the 

 deeply divided, lobed blade 

 and the network of anastomos- 

 ing veins, X 0.6. This plant oc- 

 curs on rocks at low intertidal 

 levels and below along virtu- 

 ally the entire Pacific Coast. In 

 southern CaUfomia it is infra- 

 tidal and will be encountered 

 only in drift or by dredging. 



Figure 1 69 



128 



