1922] Setchell-Gardner : Phycological Contributions 409 



adult specimens we have for study are concerned, by rhizoidal fila- 

 ments which originate from several of the lower cells of the erect 

 filaments and form complex basal masses which almost completely 

 obscure the creeping filaments. Neither the rhizoidal filaments nor 

 the creeping filaments, however, penetrate the host. The chromato- 

 phores are small and irregular in outline, seeming to be short bands 

 rather than regular disks. They are generally so closely placed in 

 the younger cells as to seem almost like a continuous band, but are 

 separate in the older cells with slender processes almost connecting 

 them to one another. The cells are short and the erect filaments and 

 their branches extend out into long hairs like whip-lashes. The lateral 

 gametangia are variable in shape, arranged much as in Ectocarpus 

 confer voides f. variabilis, but are of different dimensions. Besides the 

 characteristic Ectocarpus-iy\)e of gametangia which are lateral, there 

 occur terminal seriate gametangia of the Pylaiella-type which reach an 

 extreme length of 1.5 mm. 



Ectocarpus flocculiformis sp. nov. 



Plate 47, figure 24 



Frondibus dense caespitosis, 0.75-1.5 mm. altis, per filamenta inter- 

 texta, penetrantia, rhizoidea affixis ; filamentis erectis basi plus minusve 

 furcatis, superne simplicibus aut in plantis, maximis, ramulis paucis, 

 Curtis, alternisque instructis, basi leviter attenuatis, superne longe 

 attenuatis, non piliferis; cellulis cylindricis ad leviter doliiformibus, 

 20-25/x diam., 1-2.5-plo longioribus quam latis ; chromatophoris numer- 

 osis, in cellulis junioribus angulato-discoideis, in vetustioribus rotun- 

 datis; zoosporangiis ellipsoideis, 56-66/x longis, 35-40jU, latis, prope 

 basim filamentorum erectorum in pedicellis curtis suffultis; game- 

 tangiis ovoideis ad ellipsoideis, numerosis, sessilibus aut brevi-pedicel- 

 latis, prope basim filamentorum erectorum lateralibus, 95-110/x (usque 

 ad IdOfi) longis, 30-45ja latis. 



Growing on Codiuni fragile, the rhizoidal filaments penetrating 

 deeply into the host, among and beyond the utricles: La Jolla, Cali- 

 fornia. Type, Gardner, no. 3540 (Herb. Univ. Calif., no. 206996), 

 December. 



The nearest relative of E. floccidiformis apparently is E. cylindricus 

 f. codiophilus. One marked difference between it and any of the forms 

 of E. cylindricus is in the shape and size of the gametangia. This 

 difference, along with others of less importance perhaps, though appar- 

 ently constant, seems to be sufficient to warrant keeping it separate. 



