BOT.-VOL. II.] HUS-CASSIA TOMENTOSA L. 34I 



corresponding stage of the mother nucleus. The planes in 

 which the spindles of the daughter nuclei lie are sometimes 

 at right angles, sometimes parallel to each other. 



Finally the daughter chromosomes reach the poles and 

 become surrounded with a membrane. The chromatin is 

 in the form of granules, arranged in some places to form a 

 thread, and interconnected by bands of the same finely 

 granular substance which we saw connecting the chromo- 

 somes of the daughter nuclei. The nucleolus, which dis- 

 appeared at the time of the dissolution of the membrane of 

 the daughter nuclei, now again makes its appearance. 



The granular zone surrounds each of the four daughter 

 nuclei very much as in the stages just following the first 

 division of the mother nucleus; but instead of filling up the 

 entire space between the nuclei, it merely surrounds them, 

 leaving a clear space in the middle through which fibers 

 maybe seen running from one nucleus to the other. 



Discussion. 



In the formation, development, and subsequent behavior 

 of the spindle there are two points of special interest; the 

 nature of the multipolar spindle, and the origin of the 

 cones. 



The Nature of the Multipolar Spindle. 



In the first as well as in the second divisions of the 

 pollen-mother-cells of Cassia tomentosa there is more or 

 less approach to the spindle formation described for vege- 

 tative cells. Instead of a multipolar polyarchal spindle 

 Anlage (Strasburger, 1900, p. 121) such as we usually 

 meet with in pollen-mother-cells, we have here a more or 

 less multipolar diarchal spindle. At the very beginning we 

 meet with an indication of this. The nucleus is usually 

 ellipsoidal. The first cone (afterwards the largest cone) 

 appears ordinarily at one end of the ellipsoidal nucleus. 

 The second cone formed lies in many instances directly 

 opposite the first one, or in other cases, the cone which 



