THE VEGETABLE KINGDOM. 



365 



by minute valves of microscopic size, but of exquisite con- 

 struction, which open at the fitting moment, as represented 

 in the figure of the pollen of the gourd on page 362. 



174. Flowers protected by a Spathe. Florentine Iris: Iris I 'lor entina (Linnaeus). 



In the lily, which we have chosen as an instance (Fig. 

 167), the pistil is represented by a little column situated in 

 the centre of the flower. It consists of three parts : the 

 ovary, which forms the swollen base, and which is only the 



