i6 THE STORY OF PLANT LIFE 



is ensured by the provision of hairs and their occur- 

 rence on the underside of the leaf. 



The flower is, as has been shown in the introduc- 

 tory volume, a means of providing for the reproduc- 

 tion of the plant by the most effective means. 

 Elaborated from inconspicuous foliar and axial 

 structures, the modern flower, with its accessory 

 coloured perianth, serves to attract the visits of 

 insects, being now provided with honey and pollen 

 in the stamens, which are sufficient inducement to 

 bees, etc., to wander from one flower to another. 

 By this or other means, e.g. wind, or animals as birds, 

 slugs, etc., the pollen produced by the male essential 

 organs or stamens is transferred to the female essen- 

 tial organs or pistils with the receptive stigmas. 



By degrees the nuclear elements and protoplasm 

 in the sperm-cell carried by the pollen-tube fuse in 

 the ovule, after passing down the micropyle into the 

 ovule, with the cytoplasm and nucleus of the female 

 or egg-cell. 



The fruit, lastly, serves as the crowning act of the 

 plant's endeavour to carry on the race. After 

 pollination and effective fertilisation and division the 

 embryo develops in the embryo-sac, and there is 

 stored up in the seeds, as a rule, reserve material in 

 the form of endosperm. 



Such, in brief, is the history of the various plant 

 structures and the organs to which they give rise, in 

 relation, in particular, to the part they play in the 

 economy of the individual. 



