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short, whilst 1. 6, is extremely long which is shown by its ring 

 shape. It is my opinion that when the chromosomes are very 

 long their two parts can be united for a longer time even in meta- 

 phasis, whilst the shorter chromosomes show their two parts 

 separating at a very early stage. 



The chromosomes of H. venosum are larger than those of 

 H. auricula. 



When examining a great number of spindle figures, I was 

 astonished that the number of chromosomes was not always 7 

 and that in some cases, but rather seldom, I could discern with 

 absolute accuracy 8 and 9. Fig. II, D shows a spindle figure with 

 9 chromosomes, fig. II, E a polar view of a spindle figure, and fig. It 

 F an anaphasis with 8. It is not my intention to go further into 

 detail regarding this question just now. It is a question which can 

 be perhaps more easily solved in connection with a statement on 

 hybridization experiments. It strikes me, however, as probable that 

 this difference in the number of chromosomes depends there upon, 

 that in the prophase of the first division one or two of the long 

 double chromosomes may have been transversely segmented. 



In fig. III I have given a scheme of the reduction process in 

 H. venosum, at the same time showing the different lengths of 

 the chromosomes as described in the preceeding pages. Figs, d 

 and e represent the first division and fig. /' the second one, which 

 consists of a longitudinal division of the chromosomes. Figs, a and 

 b represent the nuclei of the germ-cells. 



It has thus become evident from a cytological investigation 

 that H. auricula and venosum show typical pollen and embryosac 

 formation. The number of chromosomes in the eggcell is then the 

 reduced one, and fertilization goes on in ordinary way. Osten- 

 feld' s (16) experiments have also made it clear, that the two species 

 in question belong to the very few representatives of this genus, 

 which could not produce seeds after castration. 



III. Apogamie Hieracia. 



It now remains to be seen, how the great number of Hieracium- 

 species acl with regard to the character of the embryosac. It has 

 been proved, that they are apogamic as far as fertilization is not 

 necessary for embryo formation. 



