THE FEMALE GAMETOPHYTE 



95 



usual 8 nuclei, of which those belonging to the morphologically 

 basal end give rise to the egg apparatus and one polar nucleus 

 (Fig. 60 G) and those belonging to the upper end fuse to form an 

 irregularly lobed nucleus which usually degenerates in situ. A sim- 

 ilar fusion takes place in Langsdorffia (Fig. 61F-7) except that some- 



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B ^ C \2») D 



Fig. 61. Development of embryo sac in Langsdorffia hypogaea. A, four-nucleate 

 stage; note three degenerating megaspores at lower end and formation of lateral 

 protuberance near upper end. B, older stage, showing entry of two basal nuclei of 

 sac into lateral arm. C, more advanced stage, showing pronounced upward growth 

 of lateral arm, which is now situated at a higher level than morphologically upper 

 end of sac; note three degenerating megaspores at lower end. D, two upper nuclei 

 of the sac, dividing. E, mature embryo sac. F-I, stages in fusion of four nuclei 

 belonging to antipodal end of embryo sac. (After Fagerlind, 1945b.) 



