188 



THE BOTANICAL MAGAZINE. 



[Vol. XXXV. Ko. 418. 



September 191G, and beared 

 sporangia first in the spring 

 1918. 



Chromosome number 



This material is not con- 

 venient for the chromosome 

 study, for the chromosomes 

 are pretty long, slender and 

 numerous. I have counted 

 about fourty three to fourty 

 five of them at the root tip of 

 7. japonica (Text- fig. 9). 



The diploid number of 

 chromosomes of /. asiatica is 

 Text-fig. 7. Female prothallium with two twenty two (Text-fig. 8), just 

 embryos (Fx 2). ^^^ ^^^^^ number which was 



Text-fig. 8. Chromosomes 

 of a root tip cell nucleus of I. 

 asiatica (Achrom. -i^xComps. 



il2). 



Text-fig. 9. Chromosomes 

 of a root tip cell nucleus of I. 

 japonica (Achrom, -fV^^o^^P'^- 



12). 



found in 7. echinosporvm, by Ekstrand (5). 



The crossing of 7. japonica with 7. asiatica and its reciprocal 

 were tried, both of which were successful, and Fi plants germinated. 

 A further study in this connection is in progress. 



Resume 



1, Some account about the mode of culture of gametophytes 

 and the method of testing their maturity were given. 



2. Isoetes japonica has five or six archegonia in a female 

 gametophyte, but sometimes more than ten. When fertilization takes 



