290 Plant Life and Evolution 



survive the clearing away of the forest cover. Be- 

 fore the ax of the pioneer these forests rapidly dis- 

 appeared, and the clearings were planted with the 

 crops upon which he depended for food, or were 

 allowed to run to grass for the subsistence of his 

 herds and flocks. In these clearings the delicate 

 plants of the shady forest perished, and the waste 

 places were gradually invaded by hordes of for- 

 eign weeds, brought in the seed, or carried on the 

 coats of the stock or in the belongings of the immi- 

 grant. These hardy foreigners have now so estab- 

 lished themselves that any one but the botanist takes 

 for granted that they are natives. Few people real- 

 ize that the majority of our familiar weeds, the 

 dandelions, daisies, buttercups, etc., are European 

 immigrants. These in many cases have proved 

 themselves so well fitted to their new home, that they 

 have almost monopolized the waste places, and have 

 invaded the cultivated lands, so that they have be- 

 come pestilent weeds. It is hard to realize that little 

 more than 300 years ago there were none of these 

 common weeds to be met with in America. With the 

 rapid extension of the settlement of the western 

 plains, due to the opening up of railroads, which 

 offered rapid transit for man and also for weeds, 

 very new conditions were met with. The exposed 

 prairie was the home of many hardy plants fitted 

 to live in the open, and many of these prairie weeds 

 sunflowers, yellow ox-eye daisies, ragweed, and 

 many others, migrated eastward and joined the 



