200 GIJMPSKS INTO PLANT-LIFE 



an All-Wise Creator for the preservation of 

 species. 



The time occupied by the passage of the pollen- 

 tube varies considerably. In the fir tribe it takes 

 nearly twelve months, in the hazel-nut and orchis 

 it requires several weeks, whilst in many other 

 plants the whole process is completed in a few 

 hours. 



One of the first results of fertilisation is a rapid 

 withering of the style and flower ; the great end 

 of the flowering period has been attained, and so 

 without further expense of energy the bright petals 

 die away. 



At the same time other external changes take 

 place, which are obvious to every observer of 

 nature. The lower end of the pistil, known as 

 the ovary, begins its second growth, and in a short 

 time swells into a large structure, the shape of 

 which varies much in different species of plants. 

 Finally, the ovary changes colour and develops 

 other characteristics quite different from its 

 former conditions. These characters have refer- 

 ence to the distribution of its seeds, and in our 

 chapter on fruits we shall learn something about 



