156 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



Common on Fiiais evanescens and Fuctis harveyanus. 

 Monterey, California. 



One of the commonest Pacific coast species; where it 

 occurs in large quantities it appears to be very destructive 

 to the " host" plant. The tufts average much smaller than 

 those of the Atlantic coast specimens, 



23. Ectocarpus granulosus {Engl. Bof.) Ag. 



Plate XXIV, Figs. 3-5. 

 Ectocarpus granulosus (Engl. Bot.), Ag., Sp. Alg. II, 1828. 45. 



Filaments 1-8 cm. high ; main branches mostly opposite, many of them 

 corticated, cells 40-75/1 broad, one-half to as long as the diameter, secondary 

 branches opposite, short, given off at wide angles, curved at the tips ; ulti- 

 mate branches secund, short and acute; plurilocular sporangia abundant, 

 sessile on the secondary and ultimate branches, broadly ovate, obliquely 

 truncate at tlie base, 60-100//. x 30 to 60//. ; unilocular sporangia wanting. 



On rocks, Costaria me)'tcnsii\ and Ncrcocystis liitkeanus, 

 Pacific Grove, California: and on Zostcra marina, San 

 Pedro, California. 



The Californian plant agrees with Dr. Farlow's variety 

 tenuis in the size and branching of the vegetative filaments, 

 but has the plurilocular sporangia of the type. 



24. Pylaiella Bory. 



Pylaiclla Bory, Diet. Class. IV, 1S25, 393. 



Plant filiform, monosiphonous, more or less branched, attached to the sub- 

 stratum by more or less branched creeping filaments. Unilocular sporangia 

 globose, seriate, arising from the transformation of a part of the vegetative 

 cells of any of the branches, opening laterally ; plurilocular sporangia oblong 

 or cylindrical, intercalary, opening laterally, or occasionally terminal and 

 opening at the apex, single or many seriate. 



25. Pylaiella littoralis densa, form, no v. 



Plate XXV, Figs, i and 2, 5 and 6. 



Vegetative filaments below densely intertwined into rope-like masses, peni- 

 cillate above, branched. Branches numerous, long, opposite or alternate, 

 bearing many short branchlets ; main filament and branches 18-25/jt, cells 

 1-3 times as long as the diameter, not at all constricted ; unilocular sporangia 

 globose, 2-15 in a series, most abundant in the branches and branchlets, 

 21-30/1 in diameter; plurilocular sporangia scarce, mostly in the main fila- 

 ment, 20-50/1 X 2o-3o,a, 2-10 or more in a chain. 



