1925] Setchell-Gardner: Melanophyceae 617 



usually wearing away, leaving the thickened (and sometimes auri- 

 culate) basal margins separated from one another, to grow on into 

 simple, or, in turn, dichotomously falsely branched fronds. 



Members of the Laminariaceae with plane blades and with false 

 branching of pseudostipes formed from the thickened lower margins 

 of the fronds. 



Setchell, Kelps of the U. S. and Alaska, 1912a, p. 151. 



Key to the Genera 



1. Pseudoblades without auricles 47. Hedophyllum (p. 617) 



1. Pseudoblades with auricles 48. Arthrothamnus (p. 619) 



47. Hedophyllum Setchell 



Holdfast of branched hapteres; stipe distinct at first, later dis- 

 appearing in some species; blade short, broad and plane, at first often 

 becoming bullate, not auriculate at the base, later giving rise to 

 branched hapteres from the lower margin, either scattered or whorled ; 

 sori basal, irregular in outline. 



Setchell, Notes on Algae, I, 1901, p. 121. 



Key to the Species 



1. Stipe very short, soon vanishing; blade sessile, often much bullate 



1. H. sessile (p. 617) 



1. Stipe longer, flat, persistent, blade subsessile 2. H. subsessile (p. 618) 



1. Hedophyllum sessile (Ag.) Setchell 

 Plate 73 



Stipe of young plant very short and much flattened, soon entirely 

 disappearing ; blade at first ovate, entire, soon splitting deeply even to 

 the base, and becoming decidedly cucullate, in age becoming ample, 

 much plicated and absolutely attached, sessile, not greatly thickened 

 at the base, giving rise to hapteres along the sessile margin, 30-50 cm. 

 (up to 15 dm.) long, and 8 dm. wide; surface of blade either per- 

 fectly smooth or with irregular bullate swellings scattered over the 

 whole blade or only the basal portion, with numerous mucilage ducts 

 surrounded by small secreting cells ; sorus extensive, basal, irregular 

 in outline. 



Growing on rocks in the middle and lower littoral and in the 

 upper sublittoral belts. Ranging from Yakutat Bay, Alaska, to Point 

 Sur, California. 



