THE ORIGIN OF THE KARYOKINETIC SPINDLE 

 IN PASSIFLORA CCERULEA LINN.^ 



BY CLARA L. WILLIAMS, M. S. 



Plates XXX\^II-XL. 



Recent work on karyokinetic division has made if appear 

 very probable that no centrosome is present in the higher 

 plants. In view of this the origin of the spindle becomes a 

 subject of especial interest. The study of karyokinesis in 

 the pollen-mother-cells of Passijlora ccertilea was taken up 

 in the hope of shedding some light on this question. The 

 origin of the spindle is the sole question considered in this 

 investigation other matters receiving only casual attention. 



Among the fixing fluids experimented with in the prepar- 

 ation of material were Wilson's sublimate-acetic, Boveri's 

 picro-acetic, Flemming's strong mixture, Flemming's strong 

 mixture diluted with an equal part of water, and 2 per cent, 

 iridium chloride. When anthers fixed in Wilson's, Bo- 

 veri's, and dilute Flemming's solutions were crushed and 

 examined in their respective fluids they showed such shrink- 

 age that these fluids were not used in making preparations. 

 Good results were obtained with iridium chloride, but no 

 better than with Flemming's strong mixture (undiluted), 

 which was used for fixing the greater part of the prepara- 

 tions studied. 



The anthers were left in the fixing fluid for twenty-four 

 hours, and afterwards washed in running water for six hours. 



1 Contributions from the Botanical Laboratories of the University of California, No. 

 4. Presented for the degree of Master of Science. Prepared under the direction of Mr. 



W. J. v. Osterhout. , » -i o 



-' [189 1 April 13, 1899. 



