THE PLAN BOOKS 
On a work of such colossal scale another 
point of definiteness can not be overlooked,— 
the precise location of the various plants 
under test. For this purpose there are concise 
memoranda showing where each selected plant 
is growing. Sometimes it will be a certain 
direction in so many feet from some certain 
fixed monument, as a tree, or a fence-post, or 
the corner of a conservatory, or what not. 
The plant, when it is finally chosen from 
among its thousands of fellows, is given a 
white streamer of cloth to distinguish it, and 
there are the usual inscribed stakes to 
identity it, but any of these might be de- 
stroyed and the plan books contain the 
definite means for determining just where 
the plant is growing. When so very many 
tests are under way at the same time and 
the aggregate number of the selected plants 
is so large, it becomes necessary to have pre- 
cision and definiteness in some indisputable 
form. 
Now and again, sheets will be found in 
which the stages of a plant’s progress are 
indicated by large capital letters—A B C, 
and so on—distributed over the page and serv- 
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