THE STUDY OF THE EVOLUTION OE THE FLOWER. 



<> 



79 



This elongation is due to the activity of tlie lower cells of tLe nucellus, wliicli, OMiiip: to 

 the contiuuous formation of transverse partitions, give rise to vertical tiers of cell.'', so 



Text-fig. 9. 



Diagrams of transverse sections showing the course o£ the vascular tissue in the female flower 



of Hehvingia rusdfoUa. (For abbreviations see p. 308.) 



'at the nucellus expands longitudinally and provides for subsequent extension, 

 hile, the lower rim of tlie inte-ument increases by cell-division to form obliq 



Mean 



{Int), whilst the 



pper 



obtains 



small extension: lie 



the intesrumo 



& 



SECOND SERIES. — BOTANY, VOL. VIII. 



2 



