THE MARINE ALG2E OF NEW ENGLAND. 171 



rising- from a creeping base, capillary, alternately decompound, branches 

 multifid, attenuate, branchlets filiform, internodes once and a half as 

 long as broad. 



Var. Westpointensis, Harv. 



More slender and delicate. 



Jackson Ferry, N. T. ; Newburyport, Mass., Harvey; Providence, E. 

 I., Mr* Olney; Gloucester, Mass. ? W. G. F. The variety at West Point. 



The present species is with difficulty distinguished from P. Olneyi, which, in its turn, 

 too closely approaches P. Harvey i. The two last-named species are attached by a 

 small disk, and the filaments do not rise from a creeping base, as in the present spe- 

 cies. The vertical filaments of P. subtilissima are of a purple color, and are fine and 

 soft, and the cells are not much longer than broad. We have seen specimens collected 

 by Mr. Olney near Providence which may with certainty be referred to the present, and 

 have found floating in ditches at Gloucester tufts of a very dark, delicate species which 

 may probably be referred to it. The specimens were apparently washed from some 

 muddy shore, but the creeping basal filaments could not . be seen. Gloucester col- 

 lectors should search for the plant in muddy ditches towards Little Good Harbor. 



P. Olneyi, Harv., Ner. Am. Bor., Part II, PL 17 b. — Bough Balls. 



Fronds brownish red, densely tufted, from two to five inches high, 

 filaments capillary, much branched, branches patent or divaricate, 

 decompound, attenuated above, with scattered slender branchlets, 

 internodes three or four times as broad below, becoming shorter above; 

 antheridia ellipsoidal, not mucronate ; cystocarps broadly ovate, nearly 

 sessile. 



On Zostera. 



From New York to Halifax, most common south of Cape Ood. 



The present species passes by numerous forms into P. Harveyi, and in spite of tho 

 marked difference in the typical forms of the two species, the question remains to bo 

 settled whether P. Olneyi is not a slender variety of P. Harveyi. In its typical form 

 P. Olneyi forms dense soft tufts, sometimes called dough-balls by the sea-shore popula- 

 tion. The filaments are divaricately branched below, but the upper branches are 

 slender and erect and beset with fine byssoid branchlets. When old, however, the 

 lower branches become rigid, and the branchlets rather spine-like, as in the next spe- 

 cies. Both P. Olneyi and P. Harveyi are very common from Cape Cod to New York, 

 growing usually on Zoslera in shallow, quiet bays. As they mature they fall from the 

 Zontera and are blown into small coves, the bottoms of which are sometimes almost 

 carpeted with the globose tufts of these two species, which lie loosely on the bottom. 

 The typical forms of the present species collapse at once when removed from the 

 water. 



P. Harveyi, Bail, j Ner. Am. Bor., Part II, PI. 17 a. — Nigger Haw. 

 PI. XV, Figs. 3, 4. 



Fronds blackish red, globosely tufted, filaments two to six inches 

 high, setaceous, when young with a leading axis, becoming divaricately 

 much branched, branches alternately decompound, patent, often angu- 

 larly bent, beset with numerous short, simple or forked, spine-like 



