Number of spindle apparatii formed during the development of angiospermic female gametophyte from megaspore.

One megaspore undergoes free nuclear mitosis to form 2 megaspore nuclei. During this phenomenon there is the formation of one spindle apparatus. Each of these nucleus will undergoes further free nuclear mitosis to form 4 nuclei. While this is occurring there is the formation of 2 more spindle apparatii. Now each of the 4 nuclei further undergoes mitosis  to form 8 nuclei. While this phenomenon is occuring there is the formation of 4 more spindle apparatii. 

In total there is formation of 1+2+4= 7 spindle apparatii.

( Note : 1 meiosis -  requires 3 spindle apparatus , 1 mitosis requires 1 spindle apparatus )