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When the old style 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 move. Some people, like 
plants and animals, are also constantly on the move. We need only think of 
the frontiersman who feels crowded when a neighbot' nioves within a mile 
of him. But this type bas 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 embankments 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 1893 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. 
When [ made a tovr through the West, in 1905, I was surprised to note 
how free the Yellowstone Park is from eur common weeds; I saw only one 
or two; evidently they are just beginning to come in. On the other hand, 
in traveling through the West, | saw a number of plants that I had pre- 
viously found as adventive plants along tlhe 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 Longcliff (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 [ 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 
