HOW TO KNOW THE SEAWEEDS 



131b Thallus branched throughout, or at least above a simple stipe. . 132 



132a Branching dichotomous to palmate or ilabellate 133 



132b Branching pinnate to irregular 139 



133a Blades with only a rather coarse midrib. 134 



133b Blades with delicate, dichotomous and sometimes anastomosing 

 veins; midrib, ii present, not percurrent 136 



134a Blades with a distinct, regular row of cryptostomata (showing as 



small tufts of hairs) on either side of the midrib. Fig. 172 



Hesperophycus harveyanus 



Fig. 172. Hesperophycus harvey- 

 anus (Decaisne) Setchell & Gard- 

 ner 



Part of a vegetative plant to 

 show the midrib and the rows 

 of cryptostomata on either side, 

 X 1.0. This is a common plant 

 on the exposed tops of upper in- 

 tertidal rocks along the coast of 

 California to as far north as Mon- 

 terey Bay. It is easily obtained 

 at almost any low tide, for it 

 grows only a few feet below high- 

 est water levels and is markedly 

 resistant to desiccation. In south- 

 ern California it is often mistaken 

 for a species of the closely re- 

 lated genus Fucus, but inasmuch 

 as Fucus is confined on our Pa- 

 cific Coast to the region north 

 of Point Conception, California, 

 Hesperophycus cannot be con- 

 fused with it to the south. A dis- 

 tictive and readily recognizable 

 character is the presence on most 

 plants of abundant, extruded para- 



physes from the rows of cryptostomata. These are usually whitish in 



color and quite conspicuous. 



Figure 172 



131 



