DIVISION I. 

 ANGIOSPERMS OR HIGHER FLOWERING PLANTS 



CHAPTER I. 



SEED. GERMINATION. FORM OF THE ESTABLISHED 



PLANT. 



The Higher Plants are called Seed-Plants, because they bear Seeds. 

 The Seed is a detachable part of the parent Plant, which contains the 

 germ of a new individual. When mature, it is usually hard and dry. 

 It can stand drying up without losing its vitality. In this state it 

 may remain dormant for a considerable period, often for years, and 

 may withstand conditions which would be unfavourable for active 

 life, such as extremes of heat and cold. But when the conditions are 

 favourable, the active life of the germ, which has been in a state of 

 suspense in the dry seed, may be resumed. The test of vitality of the 

 seed is whether or not it will germinate when exposed to suitable 

 conditions. 



If a dry seed of a Bean, such as may be bought in a seedsman's shop, 

 be dissected, its parts may be easily recognised. But the dissection 

 will be more readily carried out if it be soaked in water for twenty-four 

 hours. The effect of the soaking will be that it will increase in bulk 

 and in weight. The swelling is due to the imbibition of water, which 

 is a property of dry vegetable tissues. A distinction must be drawn 

 between such swelling and growth. Swelling by imbibition is 

 reversible process, and is not a manifestation of life. A dead b< 

 will swell equally with a living one. If either be dried again, it will 

 shrink back to its original bulk. Growth, on the other hand, is a result 

 of vital activity. It involves, as we shall see in Chapter IX., p. 139, 

 a redistribution of organic material. This is an irreversible proc. 



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