The Gathering and Storing of Seeds. 109 



165. Conditions Affecting the Duration of Seed Vi- 

 tality. A uniform degree of humidity and tempera- 

 ture tends to prolong the vital period of seeds by caus- 

 ing little drain upon the life of the living cells. Seeds 

 deeply buried in the ground are often capable of ger- 

 mination at a great age, and kidney beans at least one 

 hundred years old, taken from an herbarium, are said 

 to have germinated. In these cases, the seeds were sub- 

 jected to few variations in humidity and temperature. 



Seeds usually retain vitality longer when not re- 

 moved from their natural covering, probably because 

 they are thus exposed to fewer changes of humidity 

 and temperature. Timothy seeds, that became hulled in 

 threshing, lose vitality sooner than those that escape 

 hulling, even when the two sorts have been kept in the 

 same bag. Indian corn is said to retain vitality longer 

 on the cob than shelled, and longer when the ear is 

 unliusked than if husked. 



166. Moisture is an Enemy to Stored Seeds, except 

 for the class that requires stratification (169). A little 

 moisture in stored seeds is very liable to cause the de- 

 velopment of fungi (moulds) that may destroy the em- 

 bryo. Damp seeds are also liable to be destroyed by 

 freezing. It is important that seeds he dried promptly 

 after gathering, for if mould once starts, subsequent 

 drying may not destroy the fungus; the latter may re- 

 sume growth as soon as the seed is planted, thus en- 

 feebling or destroying the embryo before it has time 

 to germinate. Drying by moderate artificial heat (not 

 higher than 100° F.) is wise with seeds gathered in cold 

 or damp weather. 



