MITOSIS IN PLANT CELLS 77 



no means always, characterized by the absence of recognizable 

 centrosomes. The actual appearance of some of the principal 

 stages in the process is shown more highly magnified in Fig. 34, 



A. 



Nuls 



-cp 



D. E. F. 



FIG. 34. Six selected Stages in the mitotic Division of the Nucleus in the 

 growing Boot of Galtonia candicans^ X 1120. (From photographs.) 



A. Resting nucleus with large nucleolus (Nuls.). 



B. Spireme stage, with coiled dire-matin thread. 



C. The spireme thread has broken up into chromosomes which are forming the equa- 



torial plate. 



D. The chromosomes have split longitudinally and the two groups of daughter chromo- 



somes thus formed are passing to opposite poles of the spindle. 



E. Formation of the cell-plate (c.p.) across the equator of the nuclear spindle. 



F. Completion of the cell-division, and disappearance of the individual chromosomes in 



the daughter nuclei. 



which represents a series of six selected stages arranged in proper 

 sequence, reproduced from photo -micrographs. 



Fig. 34, A represents the so-called resting stage of the nucleus, 

 in which it will be noticed that there is, in addition to 

 the minute, scattered chromatin granules, a large spherical 

 chromatin nucleolus orkaryosonie (Nuls.). B shows the spireme 



