PLATE IX. 



Fig. 1. Young flower in which the pistil is not completely formed. 



Fig. 2 Very young pistil showing budding of nucellus, n 



Fig. 3. Young ovule with an arnhisporial cell {a), and showing origin of 

 the integuments {h), dermatogen of nucellus d. 



Figs. 4-5. '1 here are two archisporial cells, a. 



Fig. 6 Four archisporial cells, a; shows also decreased amount of nucel- 

 lar tissue, nt, and integuments, b. 



PLATE X. 



Fig. 7. The lower archisporium {a) developing into macrospore at the 

 expense of the other three cells, a^ 



Fig. 8. The macrospore (a) has attained nearly its full size, and only 

 rudiments of the other three cells are present, a,. 



Fig. 9. A two-celled embryo sac, a. 



Fig. 10. A four-celled embryo sac (a), the tip of which is now in close 

 relationship to dermatogen, d. 



Fig 11. An eight celled embryospsac (a), but only two cells of egg appa- 

 ratus {e) are shown. Ihree antipodal cells {at), polar nuclei which have not 

 yet united, pn. 



Fig. 12. The same as 11, but a little later stage, polar nuclei pn. in 

 process of fusion. 



Fig. 13. Mature embryo sac ready for fertilization. Egg apparatus e, 

 definutive nucleus dn, antipodals at. 



Fig. 14. Egg cell undergoing process of fertilization. Kgg nucleus en, 

 pollen nucleus />w, pollen tube//. 



rig. 15. Fertilized egg e\ endorsperm nucleus end. 



Fig. 16. Egg cell <?, endosperm, end. 



PLATE XI. 



Fig. 17. Suspensor s, embryo em, endosperm, end. 



Fig 17^. Suspensor s, embryo em. 



Fig. 18 Same os 17^, slightly older. 



Fig. 19. Embryo and endosperm a, embryo enlarged b 



Fig. 20. Nucellus, auc; integments, it, Micropyle. m; Embryosac, em; 

 funiculus, / 



