470 University of California Publications in Botany [Vol. 8 



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19. Myrionema setiferum S. and G. 



Fronds forming small, dense, irregular tufts or cushions, 0.5-0.75 

 mm. diam. ; prostrate portion composed of regularly radiating, closely 

 compacted filaments, 4r-5/x diam., 1.5-3 times as long toward the 

 margin ; true hairs unknown ; erect filaments numerous, unbranched, 

 gradually attenuated toward the apex, long-pilif erous, 700-800/x long ; 

 cells of erect filaments cylindrical, 4— 5/a diam., 2-3 times as long; 

 zoosporangia broadly clavate, 80-90/^ long, 18-24/x broad ; gametangia 

 cylindrical, 150-200ju, long, 7-8. 5/t broad, sessile, or on short pedicels 

 on the erect filaments or rarely on the creeping filaments ; loculi 

 uniseriate. 



Growing on the outer ends of the leaves of eel-grass, in company 

 with other small algae, in the lower littoral belt. Sitka, Alaska. 



Setchell and Gardner, Phyc. Cont. II, 1922, p. 345, pi. 32, fig. 8. 



Myrionema setiferum is undoubtedly very closely related to M. 

 phyllophilum on the one hand, and to 31. foecundi(.ni f. calif orniciim 

 on the other. From the former, it differs in having longer and nar- 

 rower erect filaments with longer cells and in having much longer 

 and narrower gametangia which are more frequently borne laterally 

 on the erect filaments, and often fasciculately branched from a short 

 pedicel. From the latter, it differs in having functional zoosporangia, 

 one of the few instances in which we have actually seen the undoubted 

 zoospores, in having longer and setiferous erect filaments, and longer 

 and slightly narrower gametangia. 



Myrionema globosum (Reinke) Foslie 



Myrionema {Phycocelis) glohosum Foslie, New or Crit. Norw. 

 Algae, 1894, p. 17. Ascocyclus glohosus Reinke, Algenfl. westl. Ostsee, 

 1889a, p. 46, Atlas, 1889, p. 20, pi. 17. Microspongium glohosum 

 Reinke, Die brauenen Alg., 1888, p. 20. 



Typical M. glohosum, as we understand this plant, has not been 

 reported from our territorj^ but we have described a forma afflne 

 which seems very closely related to it. 



