1917 



Muenscher; Key to Phaeophyceae 



261 



agree with Agarum Gmelini Mert. in their broad midrib, while Agarum 

 Turneri Post. & Rupr. has a narrower and more prominent midrib. Our 

 specimens compare well with Atlantic coast specimens No. Ill, Agarum 

 Turneri Post. & Rupr. in Phycotheca Boreali-Americana Collins, Holden 

 & Setchell, and also our younger stages compare with Agarum Turneri 

 Post. & Rupr. in Algae Exsic. Am. Bor., Farlow, Anderson & Eaton. Our 

 specimens also compare well with the Agarum Gmelini Mert. described and 

 illustrated by Saunders (13), p. 430, pi. 61, which belongs under Agarum 

 cribrosum Bory according to Setchell (15), who places all North American 

 forms except Agarum fimbriatum under this species. 



Young specimens about one cm. long resembling Laminaria were 

 found, and intermediate stages between these and larger specimens showed 

 that the end of the blade frays away while the plant is still young, the 

 shape of the blade soon becoming fan-like. Agarum fimbriatum plants 

 under similar conditions hardly ever fray away at the tip until they are 

 several dm. or more long, and by that time they are two or three times as 

 long as wide. 



Agarum fimbriatum 



14 



Pleurophycus Gardner! 



PLATE 52 



Fig. 13. Sketch of typical plant. X about 0.1. 

 Fig. 14. Sketch of plant. X about 0.07. 



