166 SEA MOSSES, 



Laurencia pinnatifida,* Lam. 



Frond, flattened, narrow, in specimens ten inches 

 4ong, not less than one-fourth of an inch wide ; sub- 

 stance cartilaginous, thick ; color a hvid purple, 

 becoming brownish in drying, and often faded to 

 every shade, down to a dull white, and not seldom so 

 unevenly faded, that you will get every sort of color 

 in the different parts of the same plant. The frond 

 widens somewhat upwards, arid the flattened branches 

 are often as wide as the main stem. The stem is 

 usually naked at the base, owing, no doubt, as the 

 appearance indicates, to the breaking off of the lower 

 branches. An inch or two above the base the branches 

 appear upon the edges of the flattened stem, opposite 

 or alternate, at an angle half way from horizontal to. 

 perpendicular. The branches themselves are branched 

 in the same way with flattened branchlets along their 

 edges, and in rare cases these again. The plant is 

 never more than three times pinnatifid, rarely more than 

 twice. The ends of the ultimate pinnulae are always 

 (juite blunt. 



The points indicated above will easily identify it. 

 Dr. Anderson finds it growing on Laminaria, not 

 uncommon, at all seasons, at Santa Cruz. At Santa 



* Pinnatifida = Pinnately cleft. 



