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TEXTBOOK OF BOTANY 



L.LAtiPE. 



Fig. 207. A diagrammatic representation of chromosome behavior during vegeta- 

 tive cell division. Cytoplasm omitted. 



A, non-dividing cell in which the thread-like structures ( chromonemata ) of 

 the chromosomes appear as a network (reticulum) in the colloidal medium of the 

 nucleus. B, beginning of nuclear division is evident. Some of the small connecting 

 strands of the reticulum have disappeared and the chromosomes are becoming 

 individually distinct. C, the chromosomes appear double because the longitudinal 

 division, or "splitting," of the chromosomes has already begun. D, a spindle of 

 "fibers" begins to form from the nucleus, and the nuclear membrane begins to 

 disappear. E, the chromosomes become arranged in a circle in the equatorial plane 

 of the spindle. F-G, each chromosome becomes completely divided longitudinally 

 into identical halves, or daughter chromosomes, which separate and migrate to 

 opposite poles of the cell. H, chromosomes at the poles where they become 

 reticulate and surrounded by a nuclear membrane. A cell wall develops between 

 the daughter nuclei. I, the two new cells, identical with each other and with the 

 parent cell in chromosome complement. 



Names that are often applied to different stages of cell division are: prophase, 

 B-D; metaphase, E; anaphase, F-G; telophase, H-I. 



