404 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



with numerous lateral branches and often a second series ; all 

 branches with abundant distichous ramuli, shorter above, giv- 

 ing the branches a triangular outline. Fig. 155. Me. to Fla. 



Europe. 



The best known and most widely distributed species of the 

 genus, and to which may possibly be referred, as forms, quite a 

 number of less familiar species, so no\v regarded. It is no- 

 where very abundant, but occurs in various stations ; rock} 7 tide 

 pools, muddy shores, wood work of wharves, etc. In its north- 

 ern range it seems to be more specially a summer plant, but is 

 sometimes found at any season. 



4. B. CORTICULANS Setchell, P. B.-A., No. 626. Frond 

 rather stout and coarse, up to 20 cm. high, dark green in the 

 growing parts, glossy throughout ; main stems not much 

 divided, lower part naked, upper part, usually about half of 

 the whole length, with abundant patent, generally opposite 

 branches, naked below, above with rather stout, distichous 

 ramuli, decreasing in length towards the tip of the branch ; 

 general outline of frond and of individual branches pyramidal ; 

 conspicuous tufts of descending rhizoidal filaments found at the 

 bases of the branches. Vancouver to Cal. 



Resembling B. plumosa, under which name the distichously 

 branched plant of the Pacific coast has usually been distributed ; 

 but it is a larger and coarser plant than the B. plumosa of the 

 Atlantic, and the corticating filaments are much developed, not 

 exceptional as in B. plumosa. Unfortunately, these differences 

 are of the same character as are often found between Atlantic 

 and Pacific forms of what passes for the same species ; whether 

 they are of specific importance in this case can hardly be deter- 

 mined at present. 



5. B. RAMULOSA Montagne, 18383, p. 16, PI. Ill, fig. 2 ; B. 

 plumosa var. ramulosa Harvey, 1858, p. 31, PI. XLV.A., figs. 

 4-6. Fronds densely tufted, little branched, rather coarse, dark 

 green ; ramuli uniformly short, scattered, in longer or shorter 

 secund series, or in occasional opposite pairs ; mostly in the 

 middle of the filament, seldom in the lower part or at the tip. 

 Fla., W. I. 



Ramuli very short and inconspicuous, so that the fronds seem 

 like depauperate or denuded specimens of some other species. 



6. B. LEPRIEURII Kiitzing, 1849, p. 490 ; 1856, PI. LXXV, 

 fig. 2 ; Vickers, 1908, p. 29, PI. L,. Fronds up to 15 cm. high, 



