346 THE FLOWER 



Each stamen has a stalk, the filament, and bears 

 (usually two) pairs of microsporangia, which are 

 known as pollen sacs, together forming the anther or 

 head of the stamen. When ripe the pollen sacs are full 



FIG. 57. Diagram showing the parts of a flower. 



of pollen grains (microspores) (Fig. 58, A). The 

 uppermost whorl of floral leaves, occupying the centre 

 of the flower, is called the gynaecium, 1 and its leaves the 

 carpels.^ A carpel is a folded leaf with its margins 



1 Greek, -ywrj, ywaiKos (gune, gunaikos), a woman, because the 

 female gametes are formed in the megaspores. 



Latin carpellum, a little fruit, from Greek Kaptroq, a fruit, because 

 the carpels later on grow into the fruit. 



