152 BOTAXICAL GAZETTE [august 



Fig. 7. — A slightly older embryo sac. 



Fig. 8. — An 8-nucleate embryo sac. 



Fig. 9. — Two immature embryo sacs in the same nucellus. 



Smilacina stellata 

 Fig. 10. — Cross-section of nucellus showing 2 megaspore mother cells. 



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Smilacina amplexicaulis 



Fig. 11. — Mother cell hypodermal, in synapsis. 



Fig. 12. — Two mother cells in synaptic stage in the same nucellus. 



Fig. 13. — The unequal first division of the mother cell. 



Fig. 14. — The second division of the mother cell; the cells of the first 

 division completely separated. 



Fig. 15. — Second division; cell plates between the homoeotypic nuclei. 



Fig. 16. — The 4 reduction nuclei are now contained in 2 binucleate cells; 

 the inner pair of nuclei are degenerating, while the outer pair, from which the 

 embryo sac develops, are plump and normal. 



Mianthemum canadense 



Fig. 17. — Two megaspore mother cells in synaptic condition. 



Fig. 18. — A single megaspore mother cell. 



Fig. 19. — The first division of the megaspore mother cell. 



Fig. 20.— Four fully separated cells arising from the megaspore mother 

 cell; the arrangement of the 4 cells very irregular. 



Fig. 21. — A similar stage, showing again 4 fully separated cells. 



Fig. 22. — A later stage in which the cell membranes separating the cells 

 have disappeared, causing the 4-nucleate stage of the embryo sac. 



Figs. 23, 24. — Stages in the vacuolization of the tetranucleate embryo sac. 



Fig. 25. — All immature 8-nucleate embryo sac. 



Smilacina stellata 



* 



Fig. 26. — Four megaspores fully separated by split cell plates. 

 Fig. 27. — The cell membranes of the second division have disappeared, 

 but the split cell plate of the first division still persists. 



Smilacina raccmosa 



Fig. 28. — Four unequal megaspores fully separated by split cell plates. 



Fig. 29. — A slightly later stage than the above, in which the cell membranes 

 of the second division are disappearing; the inner pair of nuclei are no longer 

 separated, while but a small part of the cell plate persists between the outer 



pair 



Streptopus roscus 

 Fig. 30. — Two fully separated daughter cells arising from the megaspor 



mother cell. 



Fig. 31. — The inner daughter cell is enlarging at the expense of the outer 



