150 SEA MOSSES. 



siphonia. If found at all north of Cape Cod, it must 

 be very rare. I found some good specimens of it at 

 Wood's Holl, the last day of July, and Dr. Farlow 

 reports it at Newport, and Noank, Conn. Miss Booth 

 at Orient Point, and in Long Island Sound. It is a 

 summer annual, and grows in deep water, from three 

 to six and eight inches high. The main stem in the 

 larger plants is as thick as a pack thread at" the base, 

 but it is soon lost in the multitude of long, large 

 spreading branches, which it throws out on every side, 

 so that there is no leading stem iti this as in the last 

 species. The primary branches are long and are them- 

 selves irregularly and profusely branched, into secondary 

 branches, which are much shorter. These again branch 

 in the same way, and the tertiary branches are usually 

 covered with spines, not unlike those of P. Harveyi. 

 But the spines are clothed with a dense growth of 

 colorless fibrills, so fine as to be individually almost 

 or quite invisible, but in the mass, border all the 

 branchlets, as they are displayed on paper, with a 

 light brown " halo " or " mist." This is the character- 

 istic point, and will identify the plant unmistakably, 

 for it is almost always present. The plant gets its 

 specific name from these fibrills. The color of the 

 plant ranges from a light to a dark brown, often even 

 to near a full black. In general appearance the plant 



