CHAPTER II. 



GERMINATION. 



THE NATTIRE OF A SEED. — IIS BTTEATION. — POTVES OF GBOWTH. — CAUSES 

 OF GEBMINATION. — TEMPERAITJEE. — LIGHT. — HXTMIDITT. —CHEMICAL 

 CHANGES. 



A SEED is a living body, separating from its parent, and 

 capable of growing into a new individual of the same species. 

 It is a reproductive fragment, or vital point, containing within 

 itself all the elements of life, which, however, can only be called 

 into action by special circumstances. 



But while it will with certainty become the same species as 

 that ia which it originated, it does not possess the power of 

 reproducing any peculiarities which may have existed in its 

 parent. For instance, the seed of a Green Gage plum will 

 grow into a new individual of the plum species, but it will not 

 produce the peculiar variety called the Green Gage. This 

 latter property is confined to leaf-buds, and seems to be owing 

 to the seed not being specially organised after the exact plan of 

 the branch on which it grew, but merely possessing the first 

 elements of such an organisation, together with an Lavariable 

 tendency towards a particular kind of development. 



Under fitting circumstances a seed grows ; that is to say, the 

 embryo which it contains swells, and bursts through its integu- 

 ments ; it then lengthens, first in a direction downwards, next 

 in an upward direction, thus forming a centre or axis round 

 which other parts are ultimately formed. No known power 

 can overcome this tendency, on the part of the embryo, to 

 elevate one portion in the air, and to bury the other in the 

 earth. It is an inherent property with which nature has 

 endowed seeds, in order to insure the young parts, when first' 



