GENETIC STUDIES IN 

 POLEMONIUM COERULEUM 



HV C. Il OSTENFELI) 



COPENHAGEN 

 (A preliminary report) 



INTRODUCTION. 



IN 1915 I obtained from the then Imperial Botanical Gardens of Petro- 

 grad a series of seed samples of Polemonium species which next year 

 were sown in the Botanical Gardens of Copenhagen. When the plants 

 flowered in 1917, it became evident that they all belonged to 

 one and the same species, viz.: Polemonium coeruleum L. Meanwhile 

 they showed great variations, and therefore I thought it worth while 

 to study their genetic behaviour. 



Polemonium coeruleum has several advantages for genetic studies: 



1. It is a perennial species; this makes it possible to compare parent 

 plants with their offspring. 



2. It has no vegetative propagation, and therefore it is easy to keep 

 close-standing individuals free from each other (when over- or 

 under-ground runners are present, a perennial species is not easy 

 to have in dense cultures). 



3. The flowers are rather large, and thus no difficulty arises when 

 removing the anthers for castrating purposes. Furthermore the 

 anthers do not open until the corolla has opened (the plant is 

 distinctly proterandric). 



4. It is self-fertile, and self-fertilized plants produce a fair amount 

 of seeds. 



The following variations were present in my cultures: 



1. Pinnate (or more correctly pinnatifid) and bipinnate (or bipinna- 

 tifid) leaves. 



2. Blue and white colour of the corolla. 



3. Well developed large (normal) corolla and very small corolla the 

 small and narrow lobes of which only protrude slightly between 

 the sepals. 



4. Perfect (hermaphrodite) flowers with long filaments and well de- 



Heredilas IV. 



