124 COLLEGE BOTANY 



Utilization of Seeds. — The fact that seeds contain food for 

 the nourishment of the seedlings makes many of them valuable 

 as food for man and live stodc. The value of seeds for this pur- 

 pose depends upon the amount and kind of stored foods, the 

 amount of indigestible materials and the absence of distasteful 

 or poisonous compounds. Beans, peasi, wheat, corn and oats are 

 among the most important seeds used for food, but the seeds of 

 many other plants are very important commercially. Peanuts, 

 cotton, castor beans and flax seeds are used extensively for the 

 manufacture of oils and other fatty products. 



Longevity of Seeds and Vitality of Seeds. — Seeds vary 

 greatly in their power to resist extremes of temperature, humid- 

 ity and light and in many other qualities. Some seeds will 

 germinate almost as soon as mature, while others require a 

 period of rest ranging from a few days to a year or longer. In 

 many cases this period of dormancy is dependent entirely on the 

 character of the seed coats. Sweet peas, cannas and odier seeds 

 will germinate mare rapidly if the seed coats are pierced or 

 scratched so as to permit the entrance of water, and nuts will 

 germinate very quickly if the stony covering is cracked. 



So'me seeds lose the power of germinating much inore 

 quickly than others. The following table shows about the limit 

 of age thptt some of our agricultural seeds can be used with safety, 

 although much older seeds will sometimes give high percentage 

 germination. Seeds of some plants have been germinated after 

 a storage period of fifty years. 



The vitality of the seed varies not only with age but with 

 the manner of harvesting and the storage. It is well known 

 that seeds from weak, diseased and immature plants are likely 

 to be weaker than seeds from healthy, mature plants and mature 



