100 



PRINCIPLES OF PLANT CULTURE 



Slightly immature seeds usually germinate sooner than 

 fully-matured ones. 



164. Length of seed viability. The viability of all 

 seeds is limited by age, but the duration of the vital 

 period varies greatly in different species. Seeds of the 

 chervil rarely germinate if much more than one year old, 

 while those of the gourd family, the tomato and celery 



