36 



GROWTH OF PLANTS 



blue grass, beet, bush clover, three clovers, tobacco, celery, and black 

 locust. In the main, seeds of the first group have only transient dormancy 

 and as a result soon germinate and perish under the soil, while those of the 

 second group have a long dormant period in the soil : the leguminous seeds, 

 because of hard coats; and blue grass, tobacco, and celery, because of the 

 need of light for germination. The beet seeds gave only 1 per cent germi- 

 nation after 20 years and only 7 per cent and 9 per cent, respectively, after 

 three and six years. 



In discussing the results after the 20-year test, Goss ^^ draws the follow- 

 ing conclusions. Depth of burial has little effect on the longevity of the 

 seeds. Seeds of cultivated plants, especially of cereals and garden legumes, 

 perish quickly in the soil, while seeds of mid plants, especially persistent 

 weeds like dock, lamb's quarter, plantain, daisy, poke, purslane, Jimson 

 weed, and ragweed, retain their vitality well. Persistent weeds cannot be 

 controlled by plowing the seeds under, for the seeds outlive any crop 

 rotation. 



Beal's buried seed project. In 1879 Dr. Beal ^^ of East Lansing, Michi- 

 gan, buried 20 sets of seeds as follows: 50 seeds each of 20 kinds of plants 

 were mixed with sand and placed in pint bottles, and the 20 uncorked 

 bottles were buried in sandy soil 20 inches deep with the mouths tilted 

 downward to avoid filling with water. It was originally planned to take up 

 a bottle every five years for vitality tests so that the experiment would 



Table 3. Beal's Buried Seeds — Results of All Germination Tests to Date. 



Plus Sign Indicates Germination 



