OLIVE COLORED ALG^. 119 



and a smaller plant from the island of Spitzbergen, 

 collected July 23rd, has them half an inch or more 

 long.' When these pencils fall away, they are 

 replaced by short, sharp, awl-like spines, set regu- 

 larly and alternately on each edge of the flattened 

 branch, pointing forward. It is, perhaps, an arctic 

 plant, but it is found in temperate waters, south of 

 Cape Cod. It is said sometimes to attain a height 

 of six feet. It is an interesting plant, and the 

 young forms are very beautiful, and adhere nicely to 

 paper in mounting. 



Desmarestia ligulata, Lam. 



This is the most common California species, and 

 exceeds in interest, if not in beauty, either of our 

 Atlantic plants already named. It grows a foot or 

 two high, flat, one-fourth to one-half inch wide, 

 beset, at intervals, along the edges, by pairs of op- 

 posite flat branches. And these, again, are more 

 thickly clothed by shorter, flat branchlets, ser- 

 rated along the edges with sharp, forward -pointing 

 teeth. 



Both the primary and secondary branches are 

 narrowed to a point at base and apex. The sub- 

 stance of the frond is thin and delicate ; the color, 

 a yellowish olive, in the specimens which I have 



