200 MYSTERIES OF THE FLOWERS 



may be sent long journeys to fertilise flowers in 

 distant countries. The Arabs save some from their 

 date-palms from year to year to dust the new crop 

 of flowers and insure the very necessary supply of 

 dates. There is a legend that pollen of dates, hemp 

 and maize has kept its vitalising power over a space 

 of eighteen years. 



But what happens after the pollen reaches the 

 stigma of a flower? By what mysterious impulse 

 is the thrill of life conveyed from the grain, down 

 through the tissues of the long style, to vivify the 

 soft and inert mass of the little ovule ? Very clever 

 observation and manipulation under the microscope 

 has revealed this mystery. 



Upon each stigma is a certain amount of mois- 

 ture, which softens the shell of the pollen grain. 

 It expands and germinates, putting forth a growth 

 called a pollen-tube, which 

 strikes root in the soft fibres of 

 the stigma and forces its way 

 downward through the style. 

 It grows at the expense of the 

 tissues of the pistil, like a para- 

 site plant. Reaching the ovary, 

 where the little ovules are wait- 

 ing, the pollen-tube usually 

 follows the outer wall, as grop- 

 FERTILISATION OF FLOWER ing in the dark it reaches down- 



