ILLINOIS NATURAL HISTORY SURVEY MANUAL 1 
grow, with a few exceptions such as arrowleaf, seeds of which 
have been found with germinating powers unimpaired after 
soaking at the bottom of a pond for seven years. Again, drift- 
wood and other floating objects may harbor fruits and seeds, 
and carry them great distances. 
It is superfluous to point out that animals play an important 
part in the dissemination of edible fleshy fruits. They also aid 
in the dispersal of seeds and fruits which are inedible. Some of 
the seeds contained in fleshy fruits are disseminated very 
effectively because they are not digested as they pass through 
the alimentary tract of birds and animals. The prickly fruits 
of burdock may be carried over great distances on the fur of 
various animals or the wool of sheep. The seeds of certain rushes 
at the water’s edge are so tiny that they may be carried from 
one pond or lake to another, mixed with mud clinging to the 
feet of wading birds. Ants disseminate such seeds as those of 
bloodroot, wild ginger and false mermaid, which have oily or 
albuminous appendages. The ants feed on these appendages 
and often carry the seeds considerable distances. 
Man is an important agent of dissemination, as he scatter s 
seeds and fruits much as other animals do. He is still more 
important, however, for his means of travel and transportation. 
Many kinds of seeds are carried on trains and some of them are 
scattered along the right of way. For this reason a railroad 
track is an excellent place to go flower hunting. One is almost 
sure to find there a flora rich in number and variety of species. 
THE NAMES OF PLANTS 
In studying large numbers of objects it is always necessary 
to classify them in some way. This is true whether the objects 
are plants, insects, rocks, bank notes or birds. In classifying 
plants, all those that are the same kind, as determined by their 
having like characteristics of leaves, flowers, stems, etc., as we 
have already discussed, are said to constitute a species. This is 
the simplest group of individuals which have descended from 
the same stock. All species that resemble one another in certain 
fundamental respects are grouped into genera. Similar genera 
are grouped into families, families into orders and the orders 
into classes. The plants discussed in the following pages need be 
grouped for our purpose no higher than families. The families 
appear in this book in order from simple to complex structured, 
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