Aug.,1922.] SINOTOO-OENOTHEBA LAMAROKTANA 97 



recognized early in the shape of cotyledones. The appearance of 

 seven mutants from one hundred and seven seeds is of a rather high 

 percentage. 



Summary 



1. The number of the pollen mother-cells with the homologous 

 chromosomes paired in the heterotypic metaphase, or with those 

 showing the regular nuclear plates are found as much as ca. 50 per cent, 

 a result which widely differs from that of the previous investigators. 



2. Ten different cases of the irregular phenomena in the behavior 

 of chromosomes on the spindles of the pollen mother-cells and the 

 embryosac mother-cells were observed. 



3. In the nucellar nuclei of this plant it was not infrequently 

 observed that the thickened long spireme first segmented into seven 

 shorter spiremes, and subsequently by the further segmentation of 

 the latter the diploid number of chromosomes were formed. 



4. The chromomeres observed in the spiremes and the chromo- 

 somes of the meiotic and somatic nuclei have no individuality. In a 

 somatic chromosome at metaphase three or four chromomeres are. 

 seen, so that the total number in a nucleus varies from forty-two 

 to fifty-six, as this plant in diploid has fourteen chromosomes. 



5. The counting of the pollen grains in the five anthers and 

 seeds in one hundred and fifteen capsules was made. The abortive 

 spores amounted to ca. 50 per cent, which agrees with the percentage 

 of abnormal mitosis in the pollen formation. The germination ex- 

 periment made with each of the seventeen capsules showed that the 

 percentage of the normal seeds was about 35 per cent. 



6. The seedlings of this plant produced some mutants ; the 

 seven O. mut. nanella-like plantlets were found in one hundred and 

 seven seedlings raised from one and the same capsule. 



The writer has the pleasure of expressing his hearty thanks to 

 Professor K. Fujii for his kindly guidance and valuable criticism. 



Postscript : Unfortunately owing to the severe damage by insects 

 in the summer 1921 none of the mutants mentioned in this paper 

 produced seeds. 



As the manuscript of the present paper was ready in last sum- 



