150 — 



II. Hieracium venosum. 



The reduction process in this species takes place in the same 

 way as in the preceding case with the difference, however, that 



the number of the 

 chromosomes is ge- 

 nerally 7. 



In the somatic 

 cells I have found 

 14 chromosomes, 

 and the chromo- 

 somes can be seen 

 especially clearly at 

 the first divisions 

 of the tapetum, 

 where they are not 

 so closely aggre- 

 gated. 



Fig. II A-D, 

 shows four different 

 heterotypic spindle 

 figures from the 

 PMC drawn up with 

 the camera. Even 

 here the chromo- 

 somes are of diffe- 

 rent size and shape. 

 Their number is in 

 three of them seven, 

 that is the reduced 

 number. Those 



chromosomes mar- 

 ked a and b are 

 especially unlike the 

 others and can al- 

 ways be easily re- 

 cognized among the 

 exami- 



Fig. III. Scheme of the fertilization and the reduction 

 process in Hieracium venosum; a, b, nuclei of the 

 germ cells: c, nucleus of the somatic cells: d, synapsis 

 stage; e. heterotypic spindle ; f, prophasis of the second 

 division: g, tetrad. 



ber of spindle figures, 

 recognize two very long 



I have found , 

 chromosomes. 



others. In 



ning a great num- 

 can 

 very 



that generally we 

 3 medium and 1 



