SPEED OF GERMINATION 



627 



peculiarities of the embryo plants in the seeds, the nature of the 

 seed coat, age, ripeness, and other causes. 



Well-ripened seeds usually germinate more rapidly than those 

 imperfectly ripened, but the reverse is the case in some instances, 

 especially if the trials are made soon after harvesting the seed. 

 Immature seeds, however, produce weak plants, and if kept 

 lose their germinating power sooner than well-grown ones. 



The results of germination tests are tabulated thus : — 



From the observations upon the above mentioned samples, it is 

 seen that although the total number of seeds capable of growth in 

 each is much the same, the speed of development is slower in the 

 second than in the first. We must always be careful to distinguish 

 between the mere capacity for germination and the rate of its pro- 

 gress, as what we desire in seeds generally is rapidity and uniform- 

 ity of speed, in order that the young plants may become attached 

 to the soil as soon as possible. Apart from the constitutional 

 weakness which slow development generally indicates, in the 

 early stages of growth plants are delicate in any case, and any- 

 thing checking their progress at that time gives opportunity for 

 attack of insects and fungi, and unfavourable conditions of soil 

 and weather often destroy lingering plants of this description. 



In estimating the energy of germination, it is usual to note 

 the number of seeds which germinate in a few days or a week, 

 as under : — 



