Aug., 1922.] 



SINOTOO— OENOTHERA LAMAECKIANA 



95 



investigtors of Oenothera. In the 

 nucellar cells of this material it was 

 not infrequently observed that the 

 thickened long spireme first segment- 

 ed into seven shorter spiremes, some 

 of which were connected directly 

 end to end as in Gates' earlier 

 results(4), and subsequently the 

 diploid number of chromosomes ap- 

 peared by the further segmentation 

 of each of the seven spiremes. Ac- 

 cordingly the chromosomes seem to 

 be already paired on their first ap- 

 pearance. 



The chromomeric , structures 

 were observed in the spiremes or 

 chromosomes of the meiotic — in 

 presynapsis, synapsis, postsynapsis 

 (Fig. 26), interkinesis, tetrad stage 

 of spore-cells (Fig. 25) etc. — as well 

 as somatic — in spireme (Text-fig. 4. b 

 and Figs. 41, 42, 43), metaphase 

 (Text-fig. 4. a and Figs. 49, 53, 54) 

 etc. — nuclei. The chromomeres in 

 the somatic nucleus varied in size 

 and number according to the stages 

 of the mitosis in a cell or in dif- 

 ferent cells. This fact shows that the chromomeres have no individual- 

 ity as was remarked 

 by Fujn(3). In this 

 plant the number of 

 chromomeres in a 

 somatic chromosome at 

 metaphase appears to 

 be three or four, so that 

 the number of chromo- 

 meres in a nucleus 



Text-fig. 4. Spiremes and chromosomes in nucellar varies from forty-two 

 nuclei showing chromomeres. X 3500. to fifty-six. 



Text-fig. 3. Two embryosac mother- 

 cells in homotypic mitosis. X 1750. 



