JAPANESE BOTANICAL LITERATURE. 



Under this heading we intend to publish, from time to time, the reviews of 

 the current botanical literature written by Japanese, published in Japan, or based 

 upon Japanese material. The reviews may be written in English, German or 

 French. 



Yamanouchi, Shigeo, The life history of Polysiphonia 

 violacea. (Bot. Gaz. Vol. 41, p. 425-433, 1906.) 

 This is the preliminary report of the author's cytological 

 studies on Polysiphonia violacea. The material was fixed chiefly 

 in Flemming's weaker solution or in weak chrom-acetic acid 

 solution. The principal points of the results obtained are as 

 follows : 



1. The germinating carpospore contains 40 chromosomes, 

 and the tetrasporic plant the same number ; so it may he in- 

 ferred that the tetrasporic plants comes from carpospores. 



2. The germinating tetraspore contains 20 chromosomes, 

 and the sexual plants (gametophytes) the same number ; so it 

 may be inferred that the sexual plants come from tetraspores. 



3. The nuclei of the gametes (sperm and carpogonium) 

 contain each 20 chromosomes. The fusion nucleus (sporophytic) 

 in the fertilized carpogonium presents 40 chromosomes, and 

 gives rise to a series of nuclei. Some of these enter the carpos- 

 pores, which are consequently a part of the sporophytic phase 

 to be continued in the tetrasporic plant. The gametophytic 

 nuclei in the central cell of the cystocarp (with 20 chromosomes) 

 either break down or form the paranematal filaments. 



4. Tetraspore formation terminates the sporophytic phase 

 with typical reduction phenomena, so that the tetraspores are 

 prepared to develop the gametophytic generation. 



5. There is thus an alternation of sexual plants (gameto- 

 phytes) with tetrasporic plants (sporophytes) in the life history 

 of Polysiphonia, and the cystocarp forms a part of the sporo- 

 phytic phase. 



The question of the alternation of generation in the Rhodo- 

 phycese is not yet settled. In the light of recent studies of 

 Williams on Dictyota the author's results may be welcomed as 

 the general phenomena of the group. Yet the fact that in 



