IQI2] 



SHARP— ORCHID EMBRYO SAC 



385 



PLATE XXIII 



Bletia Shepherdii Hook. 



Fig. 3^. — Synapsis in megaspore mother cell. 



Fig. 35. — Inner daughter cell dividing to form two megaspores. 



Fig. 36. — Functioning megaspore: outer daughter cell and megaspore 

 disorganized. 



Fig. 37. — Two-nucleate embryo sac. 



Fig. 38. — Four-nucleate embryo sac. 



Fig. 39. — Megaspore mother cell dividing equally; wall forming. 



Fig. 40. — Wall has disappeared. 



Fig. 41. — Two nuclei dividing: wall formed at first mitosis still visible 

 as a remnant in this case. 



Fig. 42. — Four-nucleate embryo sac (four megaspore nuclei). 



Fig. 43. — Six-nucleate embryo sac: micropylar nuclei have divided. 



Fig. 44. — Eight-nucleate embryo sac: no separating walls. 



Fig. 45-48. — Usual fate of the 4-nucleate embryo sac; all the nuclei 

 fuse. 



Figs. 49-53. — Abnormal sacs into which male nuclei have been discharged; 

 all the nuclei tend to fuse; pi, pollen tube; &, male nuclei. 



Fig. 54. — Young proembryo evidently having formed in a normal sac. 

 Fig. 55. — Later stage of proembryo* 



