546 ON THE EMBRYO-SAC IIS" ANGIOSPEKUS. 



Plate XXV. 



Anthemis tinctoria (continued). 



Fig. 1. The one cell now contains several nuclei, and is occupying the whole of 



the space between the integuments at expense of nucellus-cells. 



Verbascum pklornoides. 



2. Young ovule, of which integument is first about to rise ; one cell occu- 



pies the nucellus apex. 



3. The one cell referred to in fig. 2 has become divided into four super- 



posed. 



Lobelia syphilitica. 



Fig. 4. Young ovule, with integument just formed, and one large cell occupying 



the interior of nucellus. 



5. The integument is growing over : the large cell (embryo-sac mother 



cell) has cut off a cap-cell above. 



6. A little later stage. The embryo-sac mother cell is divided into three (or 



perhaps four) superposed cells ; the lower one may belong to the 

 axial row, 



7. A little later stage. The upper cap-cell is divided by a vertical wall ; 



the lowest cell is enlarging, and its contents are very granular. 



8. The granular cell divides by a very diffluent wall, which swells up and 



separates the two products : the whole is surmounted by the com- 

 pressed cap-cells. 



9. The cap-cells still discovered on the top of the embryo-sac, in which the 



two nuclei are separated by a large clear vacuole : the integument- 

 cells form an epidermis-like investing layer. 



10. The embryo-sac shortly before completion. An egg-apparatus is forming 



above; three antipodal cells are found below; and two nuclei are ap- 

 proaching one another in the protoplasm between. 



11. Similar preparation. The two nuclei are in contact in the middle part 



of sac. 



12. Ovule ready for fertilization, with a large nucleus of the embryo-sac, 



antipodal cells below, and an oosphere at base of two synergicte 

 above. 



