132 SEA MOSSES. 



2. Fronds irregularly branched. 



(a.) Frond leathery, narrow, very dark reddish 

 brown; branches in one plane, flat, 

 narrowed at base and top, bent sword- 

 shape, and often bordered with fine 

 spines; eight to twelve inches high. 



Farlowia. 



(b.) Plants smaller and narrower, branching 

 much the same as the last; secondary 

 branches, bordered with incurved spine- 

 like ramuli, much attenuated at both 

 ends. Color, very dark red. Pikea. 



3. Frond with leading stem. 



Branches long, alternate ; secondary, short, 

 alternate ; ultimate ramuli, alternate, in- 

 curved, awl-shaped, not constricted at 

 base. Microcladia. 



III. Frond filiform or cylindrical. 



1. Frond coarse, thick as pack tlircad. 



(a.) Frond divided by regular forkings, several 

 times repeated ; horny when dry, dark. 



Aluifeltia. 

 (b.) Frond with leading stem, branches short, 

 stout, tapering at both ends. Clear red. 



RJiabdonia. 



