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MANUAL OF BOTANY 



cuts off one or sometimes two cells at its apex, the innermost of 

 which represents the tapetinn. These tapetal cells sometimes 

 divide repeatedly, especially in the Gymnosperms, so that the 

 innermost cell often comes to lie deep in the tissue of the 

 nucellus. This is often, in the same group, secured by ad- 

 ditional multiplication of cells derived from the epidermis 



Fig. 927. 



Fig. 927. Early development of the anatropous ovule of Yiola. 1-6. Succes- 

 sive stages, a, b. Inner integument, c, d. Outer integument, e. s. Em- 

 bryo sac. After Kny. 



of the nucellus over the apex of the archesporium. The 

 innermost cell produced by the archesporial divisions now 

 enlarges to a considerable extent. It represents the mother 

 cell of the spores of the microsporangium. Instead of dividing 

 to form special mother cells as in the latter, it becomes itself 



