﻿iqi6] HEAT LEY— TRILLIUM CERNUUM 429 



Fig. 4.— Post-synaptic stage of megaspore mother cell; X430. 

 Fig. 5.— Second contraction in megaspore mother cell; X430. 

 Fig. 6.— Megaspore mother cell in anaphase of heterotypic division; 

 X430. 



Fig. 7. — The daughter nuclei separated by a heavy cell wall and giving 

 evidence of formation of continuous spirems; X430. 



Fig. 8— Continuous spirem in chalazal daughter nucleus; early dis- 

 integration of micropylar daughter nucleus; X430. 



Figs. 9-12. — Micropylar daughter cell unable to organize a spindle; 

 chalazal daughter cell in various phases of the homotypic division; X430. 



Figs. 13-14. — Homotypic division completed in both daughter cells, 

 resulting in axial row of 2 cells, each containing 2 megaspores; X43°- 



Fig. 15.— Outer 2 megaspores disintegrated; X43°- 



Fig. 16.— Chalazal daughter cell with its 2 megaspores functioning directly 

 as a 2 -nucleate embryo sac; X43°- 



Fig. 17. — Four-nucleate embryo sac; X430. 



Fig. 18. — Eight-nucleate embryo sac; X430. 



Fig. 19 — Mature 8-nucleate embryo sac with egg apparatus, antipodals, 

 and polars differentiated; X43°- 



