Seeds and Seedlings. 27 



will be found very difficult to remove all of the particles 

 from these hairs, so intimate is their union. The signifi- 

 cance of this close relation will be discussed in another 

 chapter. 



15. Completion of Germination. — After the roots have 

 become established in the soil, and the green leaves have 

 unfolded to the sunlight, the young plant is in position to 

 form its own food materials, and to be no longer depend- 

 ent on food provided by the parent plant. The mother 

 plant, however, often provides more than sufficient food to 

 bring the offspring to a position of independence ; for, in 

 many instances, the reserve food is not exhausted until 

 long after the leaves and roots are ready to take up their 

 office of providing new food supphes. The reserve mate- 

 rials in the cotyledons of the oak, for example, do not 

 become exhausted until the close of the second year's 

 growth. The process of germination may be considered 

 completed when the seedling is ready to provide for itself, 

 for it would be manifestly incongruous to speak of the 

 young oak at the beginning of the second year of its 

 existence as still in the process of germination. 



16. Size of Seeds. — The size of the seed appears to have 

 little or no relation to the size of the parent plant. The 

 cocoanut and cottonwood trees are both large trees when 

 fully grown, yet the cocoanut, as we find it on our market, 

 weighs about 750 grams (including the shell or stone, 

 which is not a part of the seed), while a cottonwood seed 

 as it floats from the tree weighs about 0.0015 gram. What 

 the size and rate of growth of the plant shall be depends 

 upon potentialities transmitted to the seed from the parent 

 plant that are quite beyond our powers of observation. 



