168 THE BOTANICAL MAGAZINE [Vol. xxxv. No, 417. 



Resume of the Article in Japanese. 



JiRO Ikari : — Development of Laminaria religiosa, Miyabe. 



The results, the author has obtained from the culture of zoospores 

 of Laminaria religiosa Miyabe are the same in the essential points 

 as those got by Kylin, and Sauvageau. Some points worth to be 

 mentioned may be summarized as follows : 



1. Zoospore has a clear red-eye spot on the contradiction to the 

 observations of Kyjlin & Sauvageau, and shows positive 

 heliotropisni. 



2. Embryospore germinates in a few days after liberating from 

 the mother frond. The distal end of the germinating tube 

 gradually grows up into a globose cell and the cell-contents 

 including a chromatophore is translocated into the newly 

 formed spherical part. In some with a few remains of 

 contents. Then the chromatophore is divided into two. The 

 eye-spot disappears about in this stage. The transverse 

 partition is now formed. 



3. Gametophytes are mostly dioeceous ; oospore escaped by the 

 dehiscence of oogonium, firmly adhered to the funnel shaped 

 hollow formed on the neck of oogonium, to which the base 

 of oospore fit closely up. Antheridia are sometimes formed 

 in a single continuous row after the manner of gametangium 

 of Ectocarpus with a common opening formed in the terminal 

 cell of the row. 



4. Very rarely monoecious gametophj^tes are observed. 



5. In rather high temperature of the culture medium, the 

 embryospore soon develops and takes a complicated form ; 

 on the contrary when the medium is of low temperature, the 

 development is retarded and takes less complicated form. 



6. In the young froudlets found at the natural habitat, 

 sporophytes are formed in the same way as in the culture. 

 It is question, however, that the embryospore developed into 

 a protonema like thallus as produced in the culture form. 

 The author may thus suppose the embryospore of Laminaria 

 religiosa, either soon developed to oospore, or remaining long 

 in the single or a k\^ celled state, produced the sporophytes 

 after a long interval of time. The union of two sexual 

 elements is still unknown. 



