254 



KAKL B. KRISTOFFERSON 



to each other by means of liairs. Tlie stamens standing close to each 

 otliers round the ovary, form a cupola by the membraneous appen- 

 dages of the anthers, through which the stigma is pi#shed out. The 

 cupola has an opening between the appendages of stamens. The 

 anthers open on the inside, and therefore the poljen will fall in the 

 cupola; it then passes through the above mentioned opening between 

 the anther-appendages and falls into the pollen-magazine. 



With regard to the fertilization it should be held forth that 

 V. tricolor gives no seed by isolation by parchment bags. This de- 

 pends partly on the fact that the pollen remains in the magazine, 

 which is closed in its anterior part; partly on the fact, that the well 

 developed labellum as well as the antrorsely turned inlet to the stig- 

 matic chamber lay obstacles in the way of self-pollination. When 



Q 



D 



Fig. 2. Different tj'pes of pollen-magazine. A: closed, B: almost closed, 

 C: almost open, D: open. 



pollinated with its own pollen artificially V. tricolor develops seed 

 readily. 



In V. arvensis the pollen passes the magazine and comes directly 

 to the stigmatic chamber pointing backwards. On account of the 

 feeble development of the labellum self-pollination is attained; further 

 the anthers of most of the arvensis-forms open already in the bud. 

 This explains the fact that crossings in this species are rare in nature 

 and that forms of this species generally breed true to type. 



However, the case seems to be the same in V. tricolor to a certain 

 extent. Wittuock has found about 20 forms all true-breeding, and I 

 had about 10 tricolor -lines in culture and have not been able to 

 detect any segregation in any line. Of course, crosses may occur in 

 this species as well as in others but probably they are rather rare. 



