CHAPTER XVn 



E^PBODVCTION BY SEED— POLLINATION 



The Flower (Fig. 66). — ^The essential parts of the flower 

 are the stamens and the pistil. The stamens are the male 

 reproductive organs. Each stamen typically consists of 

 a stalk, or filament, surmounted by an anther, which con- 

 tains four chambers filled with pollen. The female repro- 

 ductive organ is the pistil, which occupies the centre of 

 the flower. The most important part of the pistil is the 

 ovary, consisting of one or more closed chambers, in 

 which the ovules are developed. The ovary is generally 

 prolonged into one or more styles, each of which is ter- 

 minated by a surface specialized for the reception of the 

 pollen — -the stigma. The stigmatic surface is covered by 

 a multitude of short nipple-like hairs, secreting a sweet, 

 sticky liquid, which holds fast the pollen as soon as it 

 comes into contact with it. The outer floral structures 

 are more leaf-like, and constitute the perianth (Gr. peri, 

 round ; anthos, flower). The perianth may be either 

 green or coloured, or the outer floral leaves may be green 

 and the inner ones coloured, in which case the parts are 

 distinguished as calyx and corolla. The corolla consists 

 of a number of petals, often large and conspicuously 

 coloured, to attract insects, and frequently joined together 

 to form a tube of varying length. The calyx, formed 

 of sepals, is green, and serves chiefly for the protection 

 of the flower in the bud. 



Reproduction by Seed. 



The seed is the result of the fusion of two sexual 

 cells within the body of the ovule. One of these 

 cells — the male, or fertilizing cell — is formed within 

 the pollen-grain; the other — the female, or egg-cell 



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