CHAPTER XVII 
REPRODUCTION 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. per?, 
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 nucleus—is formed within 
the pollen-grain; the other—the female, or egg- cell 
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