5(3 Vol. XLIII., Art. 1.— K. Yenclo: 



history of Japanese species of Lamlnaria compared with that of 

 Alaria. European botanists unanimously describe the annual shed- 

 dings of the blades of Laminaria digitata, L. hyperhorea, L. saccha- 

 rina, etc., some believing and some assuming the plants as peren- 

 nial. As far as I could understand from the accounts of these 

 three species, there seems to me no actual proof to warrant the 

 assumption that their life-lengtli is more than three whole years. 

 It may live over two winters, but not three. 



About 16 species of Laminaria are found on the coasts of 

 Japan. Some of them are of great value for domestic use and 

 export, and their life history and various other points have been 

 closely studied. According to my own observations on Laminaria 

 japonica Aresch., L. angustata Kjellm., L. ochotensis Miyabe and 

 L. longlssima Miyabe, the discharge of spores from matured sori 

 takes place, as a rule, between August-November. The sporelings, 

 undoubtedly germinated from these sjDores, make their appearance 

 during January-February of the next year. The first-year blade 

 at its full length in July-September is known to the fishermen as 

 " mizu-kombu " (water laminaria) on account of its soft and thin 

 substance. It may or may not be soriferous at the end of the 

 same autumn. Before the winter, the greater part of the blade is 

 worn away and the entire frond practically ceases to develop 

 further. In the early months of next year, the transition region 

 is very active to form the second-year blade which is abrujotly and 

 considerably broader when compared with the first-year blade. 

 The latter does not remain long upon the new blade, being only 

 occasionally found by collectors. The second-year blade now in- 

 creases in length with enormous speed, so quick in L. longissima 

 as to elongate 70 feet or more in less than 5 months. In July- 

 August the blade becomes soriferous and before the end of October 



