203 



1902.] "'-''^ 



On Eisenia and. Ecklonia. 

 By 



K. Yendo, Rigakushi. 



The most interesting point in the mori)hology and development of 

 Eisenia is its branching. At the same time it plays the most important 

 part in separating the genus from all other members of EcJ:lo7iice. The 

 reason that Eisenia has been established as a new genus is essentially 

 based upon the fact that the primary lamina becomes erased as the plant 

 grew old and finally the part adjacent to the transition part becomes 

 reniform with a number of leaves on the external margins. The nearly 

 allied genus Ecklonia differs from it, as it has been thought, on the point 

 that the primary lamina remains permanently although it might undergo 

 erosion in more or less degree. 



Three species of Eddotna have been reported from the Pacific coast 

 of middle as well as south Japan : they are EcJc. Ucyclis, EcJc. cava and 

 Eck. latifalia}^ On studying these members we find Ech. Ucyclis loses its 

 primary lamina at a certain season of year and becomes forked with a 

 number of secondary lamina at. each of the branches. This forked form 

 is most familiar to the Japanese fishermen. 



The morphological and phylogenetical description of Eck. bicijclis 

 would be but to repeat the paragraphs given " On Eisenia arboria, 

 Aresch.""> and in "Notes on Kelps ''"^ by Prof. Setchell. And also it was 

 partly or fully described and figured by Martens,^> Kjellman'^ and Suringar.*) 



Eck. radiata (Turn.) J. Ag., described by Suringar in the paper 1. c. 

 (p. 1.) undoubtedly comprises several widely difl'ered forms together with 

 Eck. Ucyclis, Kjellm. He remarks in its diagnosis (1. c. p. 1.) " secundaria 

 (lamina) in stipitis apice dilatato deinde bicruri utrinque flabellata." This 

 character is to be found in Eck. bicyclis which corresponds to the forms 



1). Kjellman: Om Japans Laminariaceer. 1885. 



2). Erythea, Vol. IV. p. 129-133. p. 155-162. 1S96. 



3J. „ „ „ p. 41. 1896. 



4). Preussische Expedition nach Ostasien. Tange. p. 113. 



5). One Japans Laminariaceer. 



6). Algues du Japon. 1874. (Muss6 Eotanique de Leide. Vol. II). 



