F-b.. iPi«.i YENTU).— NOTES <>y ALdJK }^KW TO .JAr.\S\ IV. 03 



Frond linear lanceolate. 



Blade 2v5-33 /i thick P. clongnta Kylin. 



Blade 23-29 //. tliick P. tciwrn KjKr.i.M. 



Frond cordate or reniform, 



Blade 28-44 /i thick, marjjHn entire P. Icucnsticta Thuk. 



Blade 28-40 // thick, marj^n denticulated in the lower part 

 of frond P. suhorbictilatri Kjellm. 



The material on which Kjelxman has established P. tenera 

 was an article prepared for food.^^ The natural form of frond 

 was not fully recognizable to him. He defined the species to 

 be dioecious, which gave a great perplexity to us in accepting 

 his species. But by an actual examination of the original in 

 the Botanical Museum at Upsala, I could prove it to be 

 monoecious. The plant is cultivated in large scale in Japan"^ 

 and is one of the most familiar algae with us. The originals 

 of P. elongata Kylix kept in the same Herbarium are hardly 

 distinguishable from the typical form of P. tenera Kjellm. 



Again, P. suborhiculata Kjellm. is defined to be " inferne 

 distincte dentata." Very often, however, we meet a form with 

 absolutely entire margin, and thus losing the most important 

 point to discriminate it from P. leucosticta. 



In Japan, P. tenera is limited to the inland bays of less 

 salinity while P. suborhiculata is an inhabitant on the open 

 coasts. This is quite similar to the relation of P. elongata 

 with P. leucosticta on the Eui-opean coasts. I am fully con- 

 vinced by RosENVENGE^^ who regards P. elongata as a mere 

 form of P. leucosticta. It is the view of the present writer, 

 though not yet positively proved, that P. tenera might be a 

 form of P. suborhiculata due to the condition of the place where 

 it is growing, especially to the salinity of the water. 



The form which is to be identified with P. suborhiculata is 

 mostly met with on the Pacific coast of middle Japan. In the 



1) Kjrm.man: Japanska arter af Slaglet Porpliyra, p. 20. 



2) Yendo: "Postelsia," The Year Book of tlio Minn. Seaside Station, 1901, 

 p. 9.-^Id.: Cultivation of Seaweeds, &c. Econoni. Proe. of the Rov. Dublin Soc. Vol. 

 II, No. 7, 1914. 



3) Mar. Alg. of Denmark, Part I, p. 66. 



