1922] Setchell-Gardyier : Phycological Contributions 415 



Ectocarpus cylindricus f. tj^icus nom. nov. 



Fronds diffused, 1-2 mm. high ; creeping filaments superficial ; erect 

 filaments very sparingly branched above, several arising from the same 

 creeping filament, tapering slightly at the base and apex ; cells of the 

 creeping filaments 16-20/i, diam. ; cells of erect filaments cylindrical, 

 slightly constricted at the cross-walls, 2-3 times as long as broad below 

 and at the apex, 0.5-1 times in the middle of the filament ; gametangia 

 mostly on the middle and upper parts of the filaments, mostly alternate. 



Growing on Egregia Menziesii, Halidrys dioica and C]ifitose'ra 

 osmundacea. The type locality is Pacific Grove, California. 



Ectocarpus cylindricus f. codiophilus f. nov. 



Plate 46, figure 14, and Plate 49, figures 42-4.5 



Frondibus dense caespitosis, 3-5 mm. altis, per filamenta rhizoidea 

 dense intricata. hospitem penetrantibus ; filamentis erectis prope super- 

 ficiem anastomosantibus et furcatis, superne eramosis, piliferis, game- 

 tangiis plerumque prope basim filamentorum erectorum sitis. 



Growing on C odium fragile (Suringar) Hariot and C odium Set- 

 cliellii Gardner. Carmel Bay, Monterey County, California, and La 

 Jolla. San Diego County, California.* Type, Gardner, no. 3510a (Herb. 

 Univ. Calif., no. 206992), December. 



This form differs from f. typicus in having penetrating rhizoidal 

 filaments and in that the gametangia are gathered in a dense zone at 

 or near the base of the erect filaments instead of being scattered. 



Ectocarpus cylindricus f. acmaeophilus f. nov. 



Plate 49, figure 46 



Frondibus floccosis, 7-10 mm. altis; filamentis repentibus super- 

 ficialibus, filamentis erectis eramosis, diametro in parte quaque 

 similibus ; zoosporangiis ignotis ; gametangiis usque ad 270/x longis, 

 plerumque in parte superiore filamentorum erectorum oppositis. 



Growing on Acmaea sp. Carmel Bay, Monterey County, California. 

 Type, Gardner, no. 2881 (Herb. Univ. Calif., no. 206990), May. 



This form seems to be rare, at least but few specimens have been 

 detected up to the present time. It differs from f. typicus in being 

 practically unbranched, except the fructiferous branches. Where 

 branches occur, they seem to arise as the result of an injury to the 

 main filament. It differs further in that the erect filaments are more 

 nearly cylindrical throughout, and the gametangia more often opposite 

 and generally longer and proportionally narrower. 



