146 SEA MOSSES. 



Charleston Harbor, South Carolina, but is found 

 common along the southern shores of New York 

 and New England in summer. I found it abundant 

 in Providence River and at Onset Bay, and once 

 in Danversport, Mass., the only time, I believe, it 

 has ever been seen growing north of Cape Cod. 



POLYSIPHONIA ELONGATA,* GREV. 



The three Polysiphonice to be next described have, 

 according to the books, so many points of resem- 

 blance that you will be at a loss to distinguish them 

 apart if you depend upon the technical account 

 which the books give. And yet, when you have 

 once seen them, side by side, you will never again 

 have any difficulty in recognizing them, and you will 

 wonder why it is that written descriptions cannot 

 make clear differences which are so obvious to the 

 eye. The color of the three is much the same, 

 running from a dark brown, in old specimens of -P. 

 fibrillosa, through several shades of light brown to a 

 pink in some plants of both P. violacia and P. elon- 

 gata. I will try to point out the distinguishing 

 marks of the latter species, P. clongata : 



i. The main stem is robust, cartilagenous, coarse 

 as a pack-thread, and under the pocket lens visibly 



Elongata = Elongated. 



