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When the old stjie rail fences were still common, many plants found a 

 home along them ; they perished under wire fence conditions. Some species 

 may flourish for several years in wet meadows until a dry season destroys 

 them. On the other hand, dry soil plants may flourish until a wet season 

 drowns them out. Some will grow in ungrazed pastures. A number of 

 other factors might be mentioned, but it will perhaps be seen from the 

 above why some plants are constantly on the mo^•e. Some people, like 

 plants and animals, are also constantly on the mo-^-e. We need only think of 

 the frontiersman who feels crowded when a neighbor moves within a mile 

 of him. But this type has almost disappeared. 



For a number of years I have been going along the railways and rivers 

 looking for new arrivals. It is surprising to note the number of new weeds 

 that have come in and are still coming. The railways in many respects 

 furnish ideal situations. Here and there the right of way is level, alternat- 

 ing with steep, dry and gravelly embanljments and wet ditches, occasionally 

 there is a little pond ; all these furnish a variety of habitats for different 

 species. One destructive factor, however, must be considered — the annual 

 weed cutting, as required by law. This means that many plants cannot 

 thrive; they are cut off about seed time. (By the way, in my observations 

 the railways alone observe the State weed cutting laws; it is practically 

 neglected by road supervisors.) In the Proceedings (Academy of Science) 

 for 1S93 I published a list of thirty-five immigrants, of which at least half 

 a dozen subsequently became common weeds, to be found throughout the 

 county. 



W^hen I made a tour through the West, in 1905, I was surprised to note 

 how free the Yellowstone Park is from our common vreeds ; I saw only one 

 or two ; evidently they are just beginning to come in. On the other hand, 

 in traveling through the West, I saw a number of plants that I had pre- 

 viously found as adventive plants along the railways here at home. I felt 

 like greeting them as old acquaintances. I saw many plants that I felt 

 sure would come to Indiana in the course of time; in fact, as those who 

 keep track of plants well know, new ones are appearing from year to year. 



One year at Longclift" (the Northern Indiana Hospital for Insane) we 

 had a large field of Crimson Clover, the seed having been obtained from a 

 seedsman. In passing it one day I noticed a number of strange weeds and 

 I at once came to the conclusion that this Crimson Clover had been im- 

 ported from Europe. A few years later, while in Germany, I saw these 



