Much evidence has accumulated in recent years in support of the 

 doctrine of the individuality of the chromosomes. Their permanence, 

 division, and growth are now well established facts. Observations are 

 also recorded as to the relations of these individual units both in the 

 general organization of the nucleus and in regard to the possible pairing 

 of the maternal and paternal chromosomes in the somatic nuclei. Such 

 investigations are of special significance for the problems of heredity. 

 The studies here reported concerning the nuclear phenomena in Carex 

 aquatilis relate especially to the identity of the individual chromosomes 

 in all stages of nuclear development and to the fixed relative place ar- 

 rangement of these individual units. 



Juel (1900) describes and figures the principal stages of pollen 

 formation for Carex acuta and his work is all that we have on the cyto- 

 logy of the genus Carex. His figures show stages from synapsis to the 

 development of the generative cell and prove conclusively that three of 

 the microspore nuclei degenerate, thus confirming and extending the 

 work of Elfvixg (1879) and Strasburger (1884) on Heleocharis. Juel 

 does not determine the method of chromosome reduction in the hetero- 

 typic division. The chromosomes do not even appear visibly paired in 

 his figures of diakinesis. Still the general appearance of his figures for 

 Carex acuta is strikingly similar to that of the same stages as I find them 

 in Carex aquatilis. 



My material was collected in the vicinity of Madison, Wisconsin, 

 where Carex aquatilis is abundant. Tips from the large soil roots were 



