74 THE BOTANICAL MAGAZINE. ^Voi. xxxiii. xo. sss. 



once introduced this question on some Laminariaceous algae. 

 At present, the question on this famih' seems, however, to have 

 been satisfactorily settled b}' the efforts of Drew, Killian, 

 Sauvagkau, Kylin and others but of most other families of the 

 algae the problem is still left unsolved. 



In Japan, some of the marine algae are greatly valued 

 for their economic purpose^\ It is only with us in the world 

 that they are cultivated in an extensive scale. The study on 

 the life-history of such algae is a practical problem in Japan. 

 I have therefore paid special attention to this problem for 

 3'ears, and was frequently fortunate to come across good 

 material for its solution, A few of the results are already 

 published. Under the present heading, I wish to publish from 

 time to time some more of the results of my latest observations. 



In carrjang out the present study, I am indebted to Mr. 

 JiKO Ikari, an assistant professor of the Fisheries Department 

 of the Hokkaido Imperial University. To him I wish to express 

 here my cordial thanks for his taking troubles in various ways. 



Germination of Carpospores of Porphyra. 

 Report I. 



Among the marine algae cultivated in Japan, Porphyra is 

 the most important one"*. After long experiences of fishermen, 

 the practical methods of its cultivation are now fully known. 



Twigs of bamboo or other trees are planted genernliy in 

 the middle part of September in a shallow water of suitable 

 conditions for the growth of the plant. At about 40 days after 

 the twig-planting, the sporelings become visible to the naked e\'e 

 as minute specks of purplish colour on the twigs ; and in 4-0 

 days after the appearing of the sporelings the plant is large 

 enough for the harvest. If they are left on the twigs, they 

 continue their development, the propagating organs are formed, 

 reproduction completed ; and in April-May of the following j-ear 



1) Yendo: Uses of Marine Algae in J.iiian. (Postelsia, Vol. I. 1902). 



2) Kjkllman: Jaiiaii!<ka Arter af Slagtet Porphyra. 1897. Ykndo: Uses of 

 Marine Algae in Japan. 1902. 



