256 POPULAR SCIENCE MONTHLY. 



Notwithstanding the inroads that are made upon violets they 

 thrive and increase in numbers. One reason for this is that they have 

 hidden underground flowers which do not ojDen, but in which self- 

 pollination is efEected and seed produced, giving the violet an extra 

 means of reproducing its kind. The fringed polygala is also provided 

 with these hidden flowers. Many of the so-called weeds, plants which 

 have been accidentally introduced into this country, are so well fitted 

 for the struggle for existence that they have successfully combated 

 dgainst unnatural environment and have increased enormously in 

 numbers and geograj^hical distribution. Many of these, as the daisy 

 (white weed), chickory, dandelion and the thistle, as well as the native 

 golden rods and asters, are members of the compositse family. This 

 group is represented by over 10,000 species, comprising one tenth of all 

 the seed plants, each represented by many individuals of a wide range. 

 This family of plants is the most highly differentiated. Numbers of 

 small flowers are arranged in compact heads or clusters, presenting a 

 complete organization in which there is a division of labor among the 

 members of a head. They present various contrivances for cross- 

 pollination and various adaptations of the calyx into agents for seed 

 dissemination. 



In the early summer the fields are white with daisies, which later 

 are replaced by the golden rods. Their 



Midas touch hath turned the hind to gold 

 For us to have and hold. 



Quantities of golden rod, as well as daisies, asters, golden-ragwort, 

 chicory, fleabane and rudbeckia can be gathered without causing any 

 serious reduction in their numbers. The desire to possess arnifuls of 

 flowers is thereby gratified, as is also the farmer who counts these plants 

 as pests. 



