INFLORESCENCE AND FLOWERS FRUIT AND SEED. 123 



Each of the stamens consists of a slender thread 

 (filament) bearing on its top a four-chambered swollen 

 anther. This contains a yellow dust, the pollen, com- 

 posed of round grains (pollen grains), each with three 

 thinner spots in its otherwise thick wall. Each of these 

 pollen grains consists of a membrane inclosing nucleated 

 protoplasm and food materials. When ripe the wind 

 blows the pollen as it scatters from the dangling stamens, 

 and some of the grains reach the stigmas of the female 

 flowers ; here they germinate, each pollen grain sending 

 a delicate pollen-tube down the style into the ovary of 

 the flower. This process of application of the pollen 

 grains to the stigma is termed pollination, and depends 

 on the wind. 



The female inflorescences are also spikes (Fig. 32, A), 

 but they bear only one to five flowers, and stand off 

 from the axils of the foliage leaves. In the commonest 

 English variety ( Q. pedunculata) the spikes are rather 

 long, obliquely erect, and the flowers are scattered on 

 the upper end of the rachis of the spike ; in other varie- 

 ties the flowers are more clustered in the axils of the 

 leaves. Here, as in one or two other details, minute 

 differences are apparent in different individuals ; similar 

 trifling differences are met with in the structure of the 

 male flowers. 



Each female flower springs (like the male) from the 

 axil of a small bract : in other respects it is very unlike 

 the male flower. In the first place, the ovary is inferior, 

 being sunk in and fused into a six-partite perigone, the 



