278 THE BOTANICAL MAGAZINE. C y i. xxiv. No. 287. 



very remarkable. Some of them present paired arrangements 

 and form pseud o-gemini and they show even a tendency to form 

 a group of more than two. 



An abnormal case in the heterotype division has been ob- 

 served, the chromosomes are smaller than the ordinary ones 

 and two or three of them, which are especially small, take a 

 rod-shape. 



Chromosomes in the somatic cell. The somatic num- 

 ber of chromosomes is 24, but very often we find a larger 

 number. Chromosomes always present paired arrangements. 

 The chromosomes show here the difference of size and shape 

 clearly, while it was not so clear in the maiotic phase. 



Embryosac and endosperm-formation. The develop- 

 ment of the embryosac is normal. In the antipodals, which 

 consist of 3 cells at first, further cell- or nuclear divisions take 

 place, as is the case with other Gramineae. 



The ' double fertilization ' takes place in this plant, and 

 the sperm-nucleus reaches the upper polar nucleus. 



The regular appearance of the three nucleoli in the young 

 daughter-nuclei of the endosperm-tissue is looked upon as an 

 indication of the autonomy of the three different nuclei, which 

 have given rise to the endosperm-initial, up to a certain stage 

 of endosperm development. 



The endosperm-formation proceeds at first as usual with 

 free nuclear divisions, and is followed later by the simultaneous 

 wall- formation. In the further development of the tissue the cell- 

 wall formation is often suppressed, and the fusion of the 

 daughter-nuclei occurs, which results in the formation of syntri- 

 ploid nuclei. 



The present work was carried out under the guidance of 

 Professor Fujn during the academic year of 1907-1908. I wish 

 to express my obligation to him for his kind advice and 

 suggestions throughout the work. 



Botanical Institute, College of Science, 

 November, 1910. Imperial University, 



Tokyo. 



