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METHODS IN PLANT HISTOLOGY 



The Ranunculaceae, especially Anemone patens var. wolfgangiana, 

 show a rather large, broad embryo sac, with highly organized egg 

 apparatus and antipodals. Sections should be 10-20 fx thick. 



For general views of the embryo sac, the safranin, gentian violet, 

 orange combination is recommended. 



Fig. 133. — Plumbagella micrantha: longitudinal section of ovule showing the embryo sac, with 

 the egg and endosperm nucleus ready for fertilization. Stained in iron-alum haematoxylin. Eastman 

 Commercial Ortho film, Wratten E filter (orange); Bausch and Lomb 8-mm. objective, N.A. 0.50; 

 Spencer ocular X6; arc light; exposure, 1 second. Preparation by Dr. K. von O. Dahlgren and nega- 

 tive by Dr. P. J. Sedgwick. X208. 



The peculiar embryo sac of Plumbagella, with only two nuclei — the 

 egg nucleus and the endosperm nucleus — when ready for fertilization, 

 is shown in Figure 133. 



Fertilization. — The later stages cut to show the mature embryo sac 

 will often show fertilization. The male and female nuclei almost in- 



