158 



THE REPRODUCTIVE ORGANS 



which form the calyx, and which in the bud completely cover 

 and protect the other parts. The second whorl the corolla 

 consists of brightly-coloured petals, which are often 

 scented, and sometimes bear honey-secreting glands. In 

 consequence of their colour, scent, and honey, they are 

 attractive to insects. The two inner whorls differ from 

 the outer ones in an important respect. They bear repro- 

 ductive bodies called spores ; such spore-bearing organs 

 are known as sporophylls. The whorl of sporophylls 

 lying immediately within the corolla is the androecium, 

 and consists of small-stalked bodies, the stamens. Each 



Fig. 106. Transverse Sections of Anthers. 

 i, before; 2, after dehiscence; Po, pollen-grains. 



stamen has a slender stalk or filament, bearing on its free 

 end the anther ; this consists of four parallel pollen-sacs 

 (Fig. 106), or microsporangia (Gr. mikros = small, spora 

 a seed, angeion = a case), within which are a large number 

 of pollen-grains or spores (Po), whose production is the 

 special function of the stamen. These minute spores are 

 called microspores, and the organ which bears them (the 

 stamen) is the microsporophyll (Gr. phyllon = a leaf). 

 In some flowers the stamens are attractive in colour, and 

 the pollen is an important food for bees and other insects. 

 The uppermost part of the axis gives rise to sporophylls 

 of a different kind, the carpels, which together constitute 

 the gynoecium, or pistil. Usually three parts of the 



