

i9i 7] WENIGER— EUPHORBIA 281 



Fig. 27. — Mature seed in longitudinal section. 



Fig. 31. — Mature embryo. 



Fig. 32. — Pistillate flower, with ovary jointed to pedicel. 



E. splendens.—YiG. 33. — Nucellus with megaspore mother cell 2 layers 

 below epidermis. 



Fig. 34. — Megaspore mother cell with resting nucleus. 



Figs. 35, 36. — Synapsis in megaspore mother cell. 



Fig. 37. — Anaphase of heterotypic division in megaspore mother cell. 



Fig. 38. — Lowest of the 4 megaspores, which is to develop into embryo 

 sac; other 3 megaspores have disintegrated. 



Fig. 39. — Two functional megaspores side by side, each accompanied by 

 what appear to be 3 disintegrating megaspores. 



Fig. 40. — Binucleate embryo sac. 



Fig. 41. — Four-nucleate embryo sac. 



PLATE XVI 



Fig. 42. — 

 antipodal end. 

 Fig. 43. 



micropy 



formed 



about to fuse near micropy lar end; 2 daughter nuclei with cell plate near 

 antipodal end. 



Fig . 44. 



micro 



pylar end; 8 nuclei at antipodal end, 3 of which are inclosed by cell membranes. 



Fig. 45.— Polar nucleus from antipodal end approaching other polar 

 nucleus which lies close to egg apparatus. 



Fig. 46. — Polar nuclei about to fuse near egg. 



Fig. 47. — Polar nuclei fused, but 2 nucleoles still persisting; egg nucleus 

 at one end of cell. 



Fig. 48. — Fertilization: one male nucleus in contact with nucleus formed 

 by fusion of polar nuclei; other male nucleus is still in pollen tube. 



Fig. 49. — Pollen tube within embryo sac; no evidence of fertilization, 



fuse. 



distinguishable 



Fig. 50. — Fertilized egg still undivided; 2 nuclear divisions have occurred 

 endosperm. 

 Fig. 51. — First division of egg. 



Fig. 52. — Young embryo with terminal cell divided by longitudinal wall. 

 Figs. 53, 54. — Later stage in embryo development. 

 Fig. 55. — Embryo consists of rounded mass of cells at end of a short sus- 



pensor. 



Fig. 56.— Embryo has increased in size, and suspensor is beginning to 



disintegrate. 



