THE AMERICAN BOTANIST. 119 



the seeds produced must not only be strong and viable, but 

 they must escape destruction by birds, mammals, insects and 

 various elemental forces. A side-light upon this struggle is 

 found in the statement in the National Geographical Magazine 

 that the tree sparrows in a state lik Iowa eat up during the 

 winter, no less than 875 tons of weed seeds. The tree sparrow 

 is a small bird and eats for the most part minute seeds so that 

 the number of seeds in the amount mentioned is almost incon- 

 ceivable. The tree sparrow is only one of a number of seed- 

 eating birds and thus we get some idea of the vast number of 

 seeds that weeds must produce to merely hold their own in 

 the world. Conversely we may see the inestimable value of the 

 service the seed-eating birds render to agriculture. 



Seeds and. Light — New facts are constantly be- 

 ing brought to light that at first glance seems to 

 indicate that plants have perceptions of no mean 

 order. An illustration of this is found in the be- 

 havior of certain seeds with reference to light It is 

 w^ell known that plants require light for growth but seeds do 

 not need light for germination, otherwise the farmer would 

 have to plant all his seeds on the surface. Seeds of epiphytes, 

 that is, plants that grow upon other plants, seem to realize 

 that when they are in darkness they are not in a favorable posi- 

 tion for growth and therefore refuse to germinate. In some 

 experiments recently performed at the Missouri Botanical 

 Garden, seeds of the strangling fig {Ficus anrca) planted in 

 darkness refused to grow for more than 60 days, while seeds 

 of the same plant grew in nine days when planted in the light. 

 Except for difference in the light the seeds were treated the 

 same. 



