THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



VoL.V, No. 6] OCTOBER, 1909. 



Whole Series 

 Vol. XV, No. 6 



MITOSIS IN THE ROOT-TIP CELLS OF PODOPHYLLUM 

 PELTATUM. 



BY A. RICHARDS. 



Plates XV and XVI. 



(Contribution from the Botanical Laboratory of the University of Kansas.) 



''pHE work, the results of which are herein presented, was 

 * undertaken during the summer of 1907, under the direc- 

 tion of Prof. W. C. Stevens, whom I have to thank for his kind- 

 ness and much helpful advice. My thanks are also due Mr. 

 F. A. Hartman for helpful suggestions. 



In discussing the root-tip cells of Podophyllum peltatum, I 

 shall use the following outline : 

 I. Methods. 

 II. Resting cells. 



A. Nucleus. 



1. Nuclear membrane. 



2. Chromatin. 



3. Achromatin. 



4. Nucleolus. 



B. Cytosome. 



1. Cell wall. 



2. Cytoplasm. 



3. Archoplasm. 



III. Dividing cells. 



A. Prophase. 



1. Nucleus. 



2. Cytosome. 



B. Later phases of division. 



1. Chromatin. 



2. Achromatin and cytoplasm. 



IV. General considerations. 



A. Achromatic and archoplasmic structures. 



B. Individuality of chromosomes. 



(87) 



