68 SEA MOSSMS. 



III. Frond narrow, compressed or flattened. 

 Frond forked or branched, thick, tough, one 



to two feet long. " Rockweed." Fucus. 



IV. Frond filiform or thread-like. 



I. Frond Unbranched. 

 Frond four to six inches long. Sometimes 

 inflated and constricted; always covered 

 with minute dark dots. Color, yellow 

 olive. Asperococcus, 



Long, ten to twenty feet, elastic, much at- 

 tenuated at each end. Chorda. 

 2. Frond Branched. 

 (a.) Branches mostly simple. 

 Long in proportion to main stem, parts as large 

 as pack-thread. Color black. Chorddria. 

 Short in proportion to main stem. Color, 

 olive or full green. Castagnea. 

 (^.) Branches, naked, divided and sub-divided. 

 Stem and branches repeatedly forking. Color, 

 yellowish oUve, dotted over with minute 

 dark colored warts, frond six inches high. 



Stilophora. 

 Frond one to two feet long, intricately 

 branched; branches at last very small. 



Dictyosiphon. 



