1922] Setchell^Gardner : Phycological Contributions 405 



ing on a form of '' Desmarestia ligiUata." It seems to be the same as 

 the plant figured (and described) by Saunders {loc. cit.) under 

 Ectocarpus penicillatus. It is undoubtedly the same plant as that 

 described by F. S. Collins under the name E. confervoides t acumi- 

 natus which was founded on no. 235, Gardner (Herb. Univ. Calif., 

 no. 99022) collected at Whidby Island, "Washington, growing on a 

 broad form of Desmarestia. Its affinities are closely with Ectocarpus 

 confervoides f. typicus, but it has shorter cells, sharper ramuli, de- 

 cidedly constricted filaments, with the gametangia more inclined 

 toward cylindrical than is general in that form. The chromatophores 

 are more distinctly band-shaped and more separated from one another 

 than in E. confervoides. 



A few small but profusely fruiting specimens of plants seemingly 

 of this species have been found growing on Mesogloia Andersonii at 

 Neah Bay, Washington (Gardner, no. 3817). These were attached to 

 the host by means of penetrating rhizoidal filaments, particularly by 

 the descending corticating filaments. The specimens difi'er from the 

 typical form in that they are smaller, the gametangia are shorter and 

 blunter, and on separate individuals occur seriate zoosporangia( ?), 

 some of which are divided longitudinally into four loculi. Further 

 study of more material will be necessary to determine the status of 

 this form. For the present we are placing it with E. acutus. The 

 gametangia are represented on plate 49, figure 41, and the zoosporangia 

 on plate 49, figure 40. The zoosporangia are very numerous, and they 

 resemble in form those figured by Sauvageau (1896&, p. 33, reprint) 

 for Ectocarpus virescens. They, however, have a glistening appear- 

 ance, as though they were abortive or in a pathological condition, while 

 those represented by Sauvageau are producing zoospores. This con- 

 dition in which we find ours is quite common among our Pacific Coast 

 species of Ectocarpus. AVe have not yet seen a single specimen in 

 which the so-called seriate zoosporangia show any indication of pro- 

 ducing zoospores. 



Ectocarpus afSnis sp. nov. 



Plate 46, figures ]6, 17 



Frondibus minutissimis, 500-700/a altis, ad hospitem per filamenta 

 rhizoidea pauca ramosa, decolorata, implicata affixis ; filamentis ereetis 

 sparse ramosis. superne longe attenuatis, pilif eris ; ramis alternis aut 

 oppositis ; cellulis filamentorum primariorum cylindricis, basim 24-30ju, 

 diam., apice 9-11/x, in longitudine per filamentum totura variabilibus, 

 0.75-3-plo longioribus quam latis ; chromatophoris parvis. tenuibus, in 



