30 THE STORY OF THE PLANTS. 



characteristic instances which show the mode of 

 action of these important principles. 



There is a pretty w41d flower in our hedges 

 called a red campion, or " Robin Hood." Now, 

 a single red campion produces in a year three 

 thousand seeds. But there are not three thou- 

 sand times as many red campions this year as 

 last, nor will there be three thousand times as 

 many more again next season. Indeed, if an 

 annual plant had only two seeds, each of which 

 lived and produced two more, and so on contin- 

 ually, in twenty years its descendants would 

 amount to no less than a million. From all this 

 it necessarily results that a Struggle for Existence 

 must take place among plants; they fight with 

 one another for the soil, the rain, the carbon, the 

 sunshine. 



Again, take such a wild flower as this very red 

 campion. Why has it light pink petals ? The 

 reason is, to attract the insects which fertilise it. 

 Flowers, in which the pollen is carried by the 

 wind, never have brilliant or conspicuous blossoms ; 

 but flowers which are fertilised by insects have 

 almost always coloured petals to tell the insects 

 where to find the honey. How did this come 

 about? In this way, I imagine: Many plants 

 produce a sweet juice on their leaves — for exam- 

 ple, the common laurel. This juice, which is 

 probably of no particular use to them, is very 

 greedily eaten by insects. Now suppose some 

 flower, by accident at first, happened to produce 

 such sweet juice near its stamens, which (as we 

 saw) are the organs for making pollen, and also 

 near its pistil, which contains its young seeds or 

 ovules. Then insects would naturally visit it to 

 eat this sweet juice, which we commonly call 



