CYTOKINESIS OF THE POLLEN-MOTHER-CELLS 

 OF CERTAIN DICOTYLEDONS 



Clifford Harrison Farr 



Columbia University 

 (with plates 27-29) 



I. Table of contents 



I. Table of contents 253 



II. Review of the literature 253 



a. Division by cell-plate 253 



b. Cytokinesis in the algae 258 



c. Cytokinesis in the fungi 260 



d. Cytokinesis in the animals 261 



e. Theories of cell-division 263 



/. Terminology of cell-division 264 



g. Quadripartition in cryptogams 265 



h. Quadripartition in gymnosperms 268 



i. Pollen-formation in monocotyledons 269 



j. Pollen-formation in dicotyledons 273 



III. Material and methods 284 



IV. Observations on living mother-cells 285 



Technique, etc 285 



Larch 285 



Nicotiana, etc 285 



V. Thickening of the mother-walls in Nicotiana 290 



VI. The central spindles in Nicotiana 293 



VII. Constriction furrows and nuclear migration in Nicotiana 295 



VIII. Other dicotyledons 301 



IX. Discussion 303 



Similarity of animals and plants in cell-division. 



Quadripartition in dicotyledons, monocotyledons, etc. 



Conclusions based upon literature. 



Possibility of electrically charged cell-membranes. 



The mother- wall and cell-division. 



An hypothesis as to the physical chemistry of cell-plates. 



X. Literature cited 318 



XL Explanation of plates 316 



II. Review of the literature 

 a. Division by cell-plate 

 Since the notable observations of Strasburger (67a) in 1875 

 on the existence of the so-called cell-plate as a stage in the cyto- 



253 



