228 THE LIFE OF THE PLANT 



of this palm that they might be hung by the purchasers 

 among the female flowers to pollinate them ; for this 

 plan was seen to be followed by more abundant crops 

 of fruit. We call those flowers female that contain a 

 pistil which after the petals fall transforms itself into 

 fruit ; by male flowers we understand those that contain 

 only stamens which produce the fertile dust or pollen 

 and die when the flower withers. It is not, however, in 

 all plants that the male and female, the staminate and 

 pistillate, flowers are distributed on separate individuals. 

 In many cases they grow on one and the same plant, as 

 in the birch, the oak, the pine, and in maize ; while in 

 the considerable majority of plants stamens and pistils 



are found together 

 in one and the 

 same flower, i.e. the 

 flowers are herma- 

 phrodite. Such is 

 the flower shown 

 in fig. ID. 



Let us consider 

 the part played by 

 Fig. io. Stamens in the for- 



mation of the fruit. 

 A stamen, as we already saw in our first lecture, is 

 in its most perfect form a more or less well-developed 

 filament, to the end of which are attached two oblong 

 sacks, which split longitudinally and shed a kind of 

 dust, as a rule yellow in colour. Every such grain 

 of dust represents a cell, commonly spherical in form, 

 with a double wall ; the external layer is thick and 

 generally very elaborate, while the inner layer is thinner 

 and simpler. The external layer has usually some pores 

 closed with lids which can spring open on occasion. 



The pistil in its simplest and most regular form looks 

 like a bottle (figs. lo and 65, on the right-hand side). 

 Its large ovary, the inside of which is hollow, contains 



