CELL DIVISION BY FURROWING IN MAGNOLIA 
395 
1 6. Timberlake, H. G. Development and Function of the Cell Plate in Higher 
Plants. Bot. Gaz. 30: 73-99; 154-170. 1900. 
EXPLANATION OF PLATES XXX-XXXI 
Plates XXX and XXXI are photomicrographs of cells of Magnolia, all being 
pollen mother cells except figure 19. The magnification is 650, except in figures 10 
and 19. 
Plate XXXII presents drawings made with a Spencer microscope with tube 
length 17.5 cm., objective 1.5 mm. N. A. 1.30, and ocular 6 X. Magnification 900. 
Plate XXX 
Fig. I. Pachyneme of prophase of heterotypic mitosis. 
Fig. 2. Early telophase. 
Fig. 3. Nuclear membrane and orange zone forming. 
Fig. 4. Nuclei larger, orange zone disappeared. 
Fig. 5. Furrow beginning. 
Fig. 6. Furrow well formed, nuclei in resting condition. 
Fig. 7. Nuclei broader and larger. 
Fig. 8. Nuclei very broad, nucleolus large. 
Fig. 9. Anaphase of homoeotypic mitosis. 
Fig. 10. Living cell showing furrows. 
Plate XXXI 
Nuclei reorganized after second division. 
Same as Fig. 11, with spindles parallel. 
Same stage with cell spherical. 
Homoeotypic furrows forming. 
Furrow deep across heterotypic equator. 
Polar view of same stage as Fig. 13. 
Late stage in quadripartition. 
The completion of the furrow. 
Cell plate formation in a cell of the anther wall. 
Plate XXXII 
Dispireme stage following the heterotypic karyokinesis. 
After the orange zcne has disappeared and before the furrow is 
Furrow formation. 
Following the homoeotypic karyokinesis, no orange zone. 
Furrow being resumed. 
Furrows partially completed. 
Fig. II. 
Fig. 12. 
Fig. 13. 
Fig. 14. 
Fig. 15. 
Fig. 16. 
Fig. 17. 
Fig. 18. 
Fig. 19. 
Fig. 20. 
Fig. 21. 
formed. 
Fig. 22. 
Fig. 23. 
Fig. 24. 
Fig. 25. 
