HOW TO KNOW THE SEAWEEDS 



75a Branching regularly alternate, normally with a branch from each 

 cell of the main axis, at least above. Fig. 108 76 



Figure 108 



Fig. 108. Callithamnion rupicolum Anderson 



A small upper portion of a fertile plant showing regular alternate 

 branching from each cell of the main axis and the production of tetra- 

 sporangia, X 120. A common small species along the Cahfornia coast. 



This is a moderately large genus of deUcate plants of which one 

 or more species may be found along most any part of our coasts. 

 Some of the coarser and more or less corticated species will key out 

 under step 31b. 



84 



