110 



GERMINATION OF SEEDS: SEEDLINGS 



Grass type, both the stem of the epicotyl and the primary root 

 system are usually permanent. In many seedlings of this type, 

 the cotyledons are probably so much distorted in connection with 

 food storage, that they could not function as leaves if raised to the 

 light. Again, it is claimed that these seedlings can come up 

 through harder ground by not having to raise their cotyledons. 



(Fig. 104.) 



FIG. 104. Seedlings of the Pea, showing how the seedling develops and 

 the effect of different depths of planting, p, plumule; a, stem portion of 

 epicotyl; g, ground line; r, radicle. The seedling at the right is so deep in 

 the soil that it is unable to push the plumule out of the ground. 



Size of Seedlings. There is no feature in which seedlings 

 vary more than in size. This might be illustrated by placing the 

 seedling of Timothy or Clover by the side of a Coconut seedling. 

 In general, the size of the seedling corresponds to the size of the 

 seed. The size of seedlings is reckoned with in our methods of 

 planting different seeds. Thus seeds, like Corn and Beans, are 

 planted several inches deep in the soil, while seeds, like those of 

 Lettuce, Clover, and Timothy, are sown on the surface, and cov- 

 ered only lightly if at all. In small seedlings there is not enough 

 food to enable the plant to reach through thick layers of soil. 

 Tests have shown that not many Clover seedlings get through 

 the soil when the seeds are planted even 2 inches in depth. 



