HOW TO KNOW THE SEAWEEDS 





Figure 52 



Fig. 52. Callithamnion pikeanum Harvey 



A portion of an axis with a single primary lateral branch. X 1. 

 This is the coarsest of our Callithamnion species and the only one 

 with such heavy cortication. It occurs commonly on rocks at middle 

 intertidal levels along the whole Pacific Coast except southernmost 

 California. 



Figure 53 



Fig. 53. Seirospora giiffithsiana Harvey 



A small upper portion of a plant bearing seirospores. X 150. 

 Epiphytic on Zosteia and various algae from New Jersey to Cape Cod. 



52 



