﻿VOLUME LXI 



NUMBER 6 



THE 



Botanical Gazette 



JUNE igi6 



REDUCTION DIVISIONS IN THE POLLEN MOTHER 

 CELLS OF ALLIUM TRICOCCUM 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 215 



Mildred Nothtcagel 

 (WITH PLATES XXVIII-XXX AND ONE FIGURE) 



Introduction 



In accordance with a suggestion of Dr. D. M. Mother made 

 while the author was attending Indiana University during the 

 summer of 19 14, material showing the reduction divisions of 

 Allium tricoccum was examined with the idea of comparing it with 

 the results of a previous investigation of Allium cernuum (24). 

 In many stages the results were the same, but a further investi- 

 gation of other phases of the spore mother cell development has 

 forced the author to change some views previously held. 



The nuclei are large and the haploid number of chromosomes 

 is only 8; consequently, individual members or portions of the 

 spirem can be traced through various stages with less difficulty 

 than is usually encountered. 



Literature shows a great diversity of opinion as to whether or 

 not the chromosomes visibly retain their individuality throughout 

 the resting period; also concerning the structure of the resting 

 nucleus; the state of the chromatin as it enters the synaptic 

 ball; the actual time and method of reduction; and the origin 

 of the spindle fibers. These questions the author has attempted 

 to answer. 



453 



