rilE DIVISION OF THE PROTOPLAST 03 



which have been lying in various positions are drawn into many odd 

 shapes. By the close of the anaphase the tractile fibers ha\e disap- 

 peared, and the chromosomes at each pole form a close group. Hotwecii 

 the two groups lies the spindle through which they have recently passed. 

 The mechanism of their anaphasic movement will be discussed in a later 

 section. 



The telophase is the stage during which the two groups of chromo- 

 somes, after completing their anaphasic movement, reorganize as the 

 two new nuclei. Some of the alterations undergone by the chromosomes 

 in the prophase are now reversed: the matrix loses its stainability or 

 disappears, leaving the chromonemata visible, while the latter associate 

 more closely with their neighbors and form a uniform threadwork 



fk 



'F, 



^ 



Fig. 43. — Chromosomes at late prophase, metaphase (polar view), and anapha.se of 

 mitosis in microspore of Trillium. The spindle is not well shown in smear preparations of 

 this kind. (After H. E. Warmke.) 



dispersed throughout the enlarging nucleus. The presence of two 

 chromonemata in each anaphase chromosome may account for the 

 fact that in the completed telophase nucleus there often appear to be 

 more chromonemata than the known number of chromosomes. 



While the chromosomes are undergoing their transformation, other 

 telophasic changes take place. Nucleoli appear among the chromone- 

 mata as the matrix disappears, and it is known that they arise at definite 

 points on certain chromosomes. If there are two or more nucleoli, they 

 may fuse or remain separate, depending upon their relative positions. 

 The nuclear membrane arises about the group of chromosomes as the 

 telophase begins. The karolymph appears and increases in amount as 

 the nucleus enlarges, but its origin and its relation to the disappearing 

 matrix are not understood. 



The extent to which the telophasic alterations are carried varies with 

 the type of tissue and rate of division. In older regions of a root tip 

 where divisions occur slowly, a metabolic stage characterized by finely 

 dispersed chromonemata is develo])ed, whereas in regions where mitoses 

 occur in very rapid succession, a ])rophase may ])egin l)eforc the preceding 



