DISPERSAL AND GERMINATION OF SEEDS 169 



In cultivation, man cares for the " dispersal " when he plants 

 seeds, but the germination must be left to nature. 



103. Seed-dispersal. It is a well.-known fact that seeds 

 usually are " scattered," which means that they are carried 

 away from the parent plant. The advantage of seed-dis- 

 persal, as the scattering 

 in nature is called, is so 



X*??' obvious that it needs no 



explanation. It is com- 

 , " ;l -\ monly said that the dis- 



persal of seeds results in 

 carrying them " beyond 



FIG. 135. Fruit (akene) of a dandelion 

 with tufts of hair. After KEENER. 



FIG. 136. Fruit of Senecio with 

 tufts of hair. After KEENER. 



the reach of rivalry" with the parent plant. This is certainly 

 true, but it probably carries them within the reach of rivalry 

 with other plants. The safest thing to say is that seed-dispersal 

 increases the chances for successful seed-germination. Seed- 

 dispersal involves not only seeds, but very often fruits also. 

 In those fruits that open to discharge their seeds, the seeds 

 alone are carried ; but when fruits do not open, the fruit 

 itself is transported. The distances to which seeds or fruits 

 are carried from the parent plants are exceedingly variable, 



