174 Genetic Behaviour of the Hjibrid Primula Kewensis 



records of the inheritance of yellow and isabellina (taken from various 

 families and not confined to the descendants of ||). 



From heterozygous yellow plants selfed the total numbers are 

 yellow 518 : isabellina 208. From heterozygous yellow x isabellina and 

 the reciprocal cross, the total numbers are yellow 142 : isabellina 159. 



The numbers from which these totals are compiled are irregular. 

 Among 36 yellow plants selfed, the propcn-tion of yellow : isabellina 

 varies fi-om 10 yellow : 14 isabellina to 13 yellow : 1 isabellina. We 

 have not observed any relationship between the colour factor and 

 the factor for heterostyly. In those families derived from plants 

 heterozygous for yellow and thrum, the total numbers are : 

 Yellow thrum 135 : yellow pin 33. 

 Isabellina „ 32 : isabellina „ 17. 



In spite of the irregular numbers, there seems no reason to doubt 

 that yellow and isabellina are a simple allelomorphic pair. 



The results of all the crosses with |f will now be given. 



31 

 12 



F, flor. X vert. 

 homozygous yellow 



18 

 12* 



Fi. 26 plants all yellow. 



Of these 13 plants were bred from. Twelve gave yellows only ; one 



plant gave 



28 yellow as in floribunda. 



2 dark yellow as in {| . 



9 pale yellow. 



1 lemon. 



37 

 12 



18 

 12 



F^flor. xvert. 



heterozygous yellow 



Fi. 28 plants all yellow. 



Of these 9 plants were bred from. Four gave yellows only. Four 



gave yellows and isabellina, the total numbers being 45 yellow: 18 



isabellina. One (f|) gave 



24 yellow. 



6 lemon. 



7 isabellina. 



32 r F.flor. xvert. 1 18 

 12 heterozygous yellow 12 " 



Fj = 5 yellow': 2 isabellina. 



Two yellow plants were bred from and gave yellows only. 



