On the Behavior of Chromosomes in the 

 Meiotic Phase of Some Artificially 

 Raised Papaver Hybrids. 



(Contributions to Cytology and Genetics from the Departments 

 of Plant-Morphology and of Genetics, Botanical Institute^ Science 

 College, Tokyo Imperial University. No. 38.) 



By 



Koiio Yasui 



{With Plate III and one Text-figure) 



Since Rosenberg's well known cytological studies on Droscra 

 appeared in 1904, important contributions to the cytology of hybrid 

 plants have been made by several authors, e. g., Gates (1907, 1909) 

 and Geerts (1909, 1911) on Oenothera, Digby (1912) on Primula, 

 Rosenberg (1917) on Hicracium, Kuwada (1919) on Zea, Kihara 

 (1920, 1921) on Triticum ; and the importance of the study in this 

 direction is now rapidly increasing, especially with regard to the 

 Cjuestion of sterility of hybrid organisms and the origin of variations 

 or new forms due to hybridization. 



The present paper deals with some of the results of studies of 

 certain Papaver hybrids, carried on since 1919, under the direction of 

 Prof. Fujii, with a view to some knowledge of the internal mechanism 

 of genetics of hybrids. 



Materials and Methods ' 



The parent plants in this experiment were Papaver orientale L., 

 P. somniferum L., and P. Rhoeas L. ; but the present paper is 

 limited to the account concerning the Fi Plants between P. orientale 

 and P. somniferum. 



The diagnosis given below are limited to the characteristics to 

 be considered in the present experiment. 



Papaver orientale L. Perennial herb. Stem and leaf stiflf-hairy. 

 Leaves deep green, hispid pinnately cut. Sepals 2 as a rule. 



