19-5] SetchcU-Gardncr: MeJanopJnjceae 451 



without a sheath ; zoosporangia ( ? ) narrowly clavate, sessile, 22-28|U. 

 long, 8-12ja broad at the apex ; gametangia numerous, closely crowded, 

 cylindrical, sessile on the horizontal layer, 45-55/1, long, 5-6.5/i, broad ; 

 loculi uniseriate. 



Growing within the lamina of Hedopliylhim sessile (Aresch.) 

 Setchell, near the outer end. Neah Bay, Washington. 



Setchell and Gardner, Phyc. Cont. V, 1922, p. 395, pi. 44, figs. 8, 9. 

 Phycacelis fecunda Tilden, Amer. Alg. (Exsicc), no. 356 from 

 Victoria, B. C. (determined by De Alton Saunders). 



Strehlonetna aecidiaides f. pmificuni seems very closely related to 

 the Ectocarpus aecklioides of Rosenvinge (1893, p. 894), found grow- 

 ing in Greenland on Laminarm longicruris and L. groenlandica. It 

 differs only in minor details as to the dimensions of the parts. Regard- 

 ing the zoosporangia we have to speak with uncertainty. As figured 

 by Rosenvinge, the Greenland plant has them well developed and 

 producing zoospores. They are in distinct "aecidia" and apparently 

 on distinct non-sexual plants. In our species they likewise appear to 

 be on non-sexual plants. In ours there is no indication of the produc- 

 tion of zoospores. The plants are possibly too young, or possibly they 

 bear abortive organs so commonly met with in various other genera 

 on our coast, the nature of which is still an open question. This 

 form seems to enter the host from the surface and after penetrating 

 to the second layer of cells spreads out horizontally between the sur- 

 face layer and the second layer. Later, filaments arise from the 

 under side of this layer and penetrate among the cells of the host, 

 apparently never entering them. Finally from the upper surface each 

 cell in the central region of the layer gives rise to a filament and the 

 mass acting together lifts up the surface layer of cells of the host, 

 forming a small blister which finally ruptures, as in the case of Rosen- 

 vinge 's plants. The erect filaments are almost simultaneously trans- 

 formed into gametangia, except a few in the center which develop 

 into hairs. 



Foslie (1894, p. 167, 23 in reprint) describes forms of the same 

 species found growing on Laminaria saccharincn at Kjelvik and at 

 Lyng0 near Troms0, Norway. These he listed under Ectocarpus 

 (Strehloncma) aecidiaides Rosenvinge. The measurements of the 

 parts of his forms average, in general, a little larger than those of 

 ' Rosenvinge. De-Toni (1895, p. 577) cites these Arctic plants under 

 Strehlanema aecidioides (Rosenv.) Foslie. Foslie gives 80/i, as the 

 extreme length of the gametangia. 



