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/v. 



Fio. 21. — Lilium philaJelphicum. A, ovule before the appearance of integuments, 

 showing a single hypodermal archesporial cell which is also the megaspore mother- 

 cell. B, beginning of inner integument. C, beginning of outer integument. D, E, 

 later stages. F, G, the ovule anatropous and the megaspore germinating, x 175. 

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