482 University of California Publications in Botany [yoh. 8 



times as long, 11-13/* diam. at the apex, and 1-1.5 times as long, many 

 cells in the upper part of the filaments dividing 1-2 times longitudin- 

 ally ; chromatophores band-shaped, few in a cell ; zoosporangia very 

 abundant, very variable in shape and size, narrowly ellipsoidal, clavate 

 to broadly ovoid, 40-130ju, long, 20-35/x wide, sessile or on short pedicels 

 from the prostrate filaments, or lateral or terminal on the erect fila- 

 ments ; gametangia rare, cylindrical, sessile or mostly short-pedicellate 

 on the creeping filaments, rarely terminal and tuberculate on the erect 

 filaments, 80-130ja long, 11-15/* broad. 



Growing on the pneumatocyst of Nereo'cystis Luetkeana. Neah 

 Bay, Washington. 



Setchell and Gardner, Phyc. Cont. Ill, 1922, p. 357, pi. 36, figs. 3-8. 



The unusual condition in Compsonema prevails in C. sporangi- 

 iferum. The gametangia seem to be of rare occurrence. Examination 

 of specimens of different sizes from different parts of the host revealed 

 the presence of a large number of zoosporangia in all stages of develop- 

 ment, many being empty. The gametangia are prevailingly near the 

 base, although occasionally a complex one appears terminal on an 

 erect filament. A very common character is the division of the cells 

 in the upper parts of the filaments into 2-4 parts by longitudinal walls, 

 producing a slight clavate condition in such filaments. We do not 

 know, at present, the morphological significance of this condition. The 

 zoosporangia and gametangia, so far as observed, develop on distinct 

 individuals. 



13. Compsonema intricatum S. and G. 



Fronds 1.5-2.5 mm. high, more or less confluent, forming a con- 

 tinuous velvety stratum of indefinite expansion; creeping filaments 

 numerous, profusely branched, crooked; erect filaments numerous, 

 unbranehed or with a few short branches near the base, straight, grad- 

 ually attenuated at the apices, pilif erous in part ; true hairs absent ; 

 cells of creeping filaments irregular in shape and size ; cells of erect 

 filaments cylindrical, 8-9/* diam., 1-2.5 times as long, slightly narrower 

 at the base of the filaments ; chromatophores band-shaped ; zoo- 

 sporangia ovoid to ellipsoidal, terminal on short filaments from the 

 creeping filaments or lateral and sessile or pedicellate on the erect 

 filaments near the base, 25-33/x long, 18-22/* broad ; gametangia ter- 

 minal on short erect filaments from the creeping filaments, lateral and 

 sessile or pedicellate near the base of the erect filaments or intercalary 

 in the main erect filaments, 80-120/* (up to 175/*) long, lO-14/i broad ; 

 terminal and intercalary ones up to 600./* long ; loculi mostly 2-seriate. 



