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BOTANY 



endosperm. If the student is a vefy careful observer, 

 he may be able to make out the number of cotyledons 

 in the young plant. There are fifteen seed leaves in 

 one common species of pine. The number and position 

 are better seen in a young seedling of three or four 

 weeks' growth. 



The Uses of Seeds. — Some of the uses of 

 seeds to man have already been noted. A seed 

 is a very young plant usually provided with a 

 store of food to give it a start in life. Its use to 

 the parent plant is incalculable, for it is by 

 means of the seed that a plant reproduces its 

 kind. This can be done, as we shall see later, 

 to a limited degree by cuttings, grafting, and in 

 other ways, but the usual way is by the produc- 

 tion and planting of seeds. Not only does a 

 seed serve to continue a species of plant in a cer- 

 tain locality^ but it serves to give the plant a 

 Pine seedling. foothold in uew places. Seeds may be blown 



by the wind or carried by animals, or by a hundred devices work 

 their way to pastures new, there to establish outposts of their 

 kind. 



Immense numbers of seeds may be produced by a single plant. 

 This may be of great economic importance. A single pea plant 

 may produce twenty pods, each containing from six to eight 

 seeds. This would mean the possibility of nearly twenty-five 

 thousand plants produced from the original parent by the end of 

 the second season. A plant of Indian corn may produce over 

 fifteen hundred grains of corn. On the other hand, many weeds 

 produce seed in still greater numbers. A single milkweed may 

 set free over two thousand seeds. A single capsule of Jimson 

 weed has been found to hold over six hundred seeds. The thistle 

 is even more prolific. 



Some seeds, especially those of weeds, are able to withstand 

 great extremes of heat and cold and still to retain their ability to 

 germinate. Some have been known to retain their vitality for 

 over fifty years. In plants, the seeds of which show unusual 

 hardiness, it is found that the food supply is often so placed as 



