18 C. H. OSTENFELD 



velopod anthers and female 1 lowers with short and barren (rudi- 

 mentary) stamens. 



These factors may be combined in different ways. 

 It is well known that P. coerulcum L. is a very variable »spe- 

 cies», and many forms (varieties) have been described. In »Das Pflan- 

 zenreich» we find that A. Brand (1907) has tried to arrange the dif- 

 ferent variations into a system, but they do not agree with the 

 variations here mentioned with the exception of the bipinnate form, 

 which is treated as a separate species, viz. P. sibiriciim D. Don; about 

 this Brand states: »Eine aus P. coerulcum durch Kultur entstandene 

 Art; von der Stammform im Habitus ausserordentlich verschieden». 

 About the genetic behaviour of the forms of P. coerulcum very 

 little seems to be known. The only experiments of which I know, 

 are mentioned by K. V. O. Dahlgren (1918) who refers to some ex- 

 periments carried out by H. de Vries (1900) and adds his own ex- 

 perience. DE Vries crossed the blue-flowered form with the white- 

 flowered one, and found that in Fi the blue colour was dominant. 

 Dahlgren made the same cross with the same result and also raised 

 the Fo-generation, in which a simple mendelian splitting occurred. He 

 got 108 blue and 39 white (the theoretical numbers are 110,25 and 



36,75). 



My own experiments are still only in the beginning, as I have had 

 very little time to spare and only restricted space for cultures. When 

 I nevertheless already now publish a short preliminary report on 

 my experiments, it is mainly because / wish to ask assistance from 

 other botanists to obtain seeds of forms of P. coeruleum and of other 

 species of the genus. I shall be very much obliged for such help. 



DESCRIPTION OF THE VARIATIONS. 



1. Variations in the vegetative parts. 



As mentioned above a form with bipinnate leaves is present 

 in my cultures; in this form (sibiricum) the folioles are not entire, 

 but have split up into linear segments (see Fig. 1). This striking fea- 

 ture is well known in many plants. I need only mention, as examples, 

 the laciniate form of Chelidonium majus, further a corresponding 

 form (R. laciniatus) of Rubus vulgaris Whe., and Sambucus nigra 

 L. var. laciniata. Forms of that kind have, most probably, origi- 

 nated as mutants and have been kept in cultivation for ornamental 

 reasons. 



Beside this variation my Polemonium cultures show that it 



