. 







Gerietical Studies in JPorttilaca graiidiflora. 



By 



Kono Yasui. 



(With Plate I and one Text-Figure.) 



(Contributions to Cytology and Genetics from the Departments of Plant- 

 Morphology and of Genetics, Botanical Institute, Science College, Tokyo Imperial 

 University. No. 31.) 



Portulaca grandiflora, Hook, is a common garden plant in Japan. 

 Its flowers are of various colours, such as white, \ellow, orange, pink, 

 red and variegated, and may be single or double. In addition to 

 this, the plant is annual, so that it appears to be one of the con- 

 venient materials for genetical studies. Nevertheless, the record of 

 such studies, as far as I am aware, is very scanty, Professor Ikeno's 

 brief account on this plant in his " Zikken-Idengaku " (Japanese), a 

 well known text-book on Genetics in Japan, being the only one 

 hitherto published. 



In the present research, it became clear that the plant with the 

 magenta flower results from the crossing between the white and 

 the pale yellow ; also the dominancy of the doubleness of the flower 

 to the singleness was determined with the support of numerical data, 

 both of which seems not to be common ; so it may not be out of 

 place to present here some of the results arrived at in the following 

 pages. 



MATERIALS 



Materials, used in the present experiments, were kindly given to 

 me by Professor Fujn, who collected them in 1916 and selfed them 

 once except the double-flowered race. There were the following seven 

 races named after the colour of the petal and the singleness or 

 doubleness of the flower : 



1. White double. 



2. White single. 



3. Deep magenta (tyrian rose) 1 single. 



n FipO* 



1) (The names of the colours in blackets are after Bidgway's Colour-standard 

 and Nomenclature 1912). 



