1^-5] SetcheU-Gardner: Melanophyceae 423 



EctocarpuH flageUiferus, while resembling superficially some of the 

 shortest plants of Ectocarpiis confervaides f. variabilis, presents sev- 

 eral peculiarities which are characteristic. The plants of this species 

 are attached, so far as the adult specimens we have for study are 

 concerned, by rhizoidal filaments 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 chromatophores 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 M'hip- 

 lashes. The lateral gametangia are variable in shape, arranged much 

 as in Ectocarpics confervoides f. variabilis, Init are of different dimen- 

 sions. Besides the characteristic Ectacarpiis-tyiie of gametangia 

 which are lateral, there occur terminal seriate gametangia of the 

 PylaieUa-type W'hich reach an extreme length of 1.5 mm. 



12. Ectocarpus Mesogloiae S. and G. 



Fronds minute, 0.75-1.5 mm. high, attached by a mass of densely 

 intertwined, branched, rhizoidal filaments penetrating among the cells 

 of the host ; erect filaments sparingly and alternately branched ; main 

 filaments and ramiili tapering gradually upward, very acute, not 

 piliferous; cells cylindrical, slightly constricted at the dissepiments, 

 15-18/A diara. at the base, 1-2 times as long, 4— 6/x at the apices of the 

 filaments ; chromatophores thin, irregular bands, nearly covering the 

 cell ; zoosporangia" unknown ; gametangia narrowly cylindrico-conical, 

 120-1 GOjU, (up to 210ju,) long, 18-22/x broad, on short pedicels, rarely 

 sessile. 



Growing on MyriogJoia Andersonii (Farlow) Kuck. Carrael Bay, 

 Monterey County, California. 



Setchell and Gardner, Phyc. Cont. VI, 1922, p. 411, pi. 45, figs. 5, 6. 



The general characters of this diminutive species ally it with the 

 E. confervaides group. We have deemed it best to consider it a dis- 

 tinct species on account of the small dimensions of all of its parts and 

 its penetrating habits. It has not been seen on any other host except 

 the one mentioned above. 



