Figure 8. Transverse section ( in a photomicrograph at top and diagram be- 

 low) of the apical meristem of a rhizome of Nuphar liitea (L.) Sm., showing 

 the sequence of primordia (1, 2, 3, etc., in the order of increasing age). 

 Flower bud primordia (F) originate in leaf sites in the genetic spiral, a, 

 center of apical meristem; I^, position of next primordium to appear. (By 

 courtesy of Dr. E. G. Cutter.) 



