PART III. 
KEY, CLASSIFICATION AND DESCRIPTION 
OF THE SPECIES. 
Method of Using the Key. 
IRST read all the statements following the stars (*) 
at the beginning of the Key; decide which one of 
the statements best suits the specimen you have. At the 
end of the chosen one there is a single or double letter 
in parenthesis. Somewhere below, this letter is used two 
or more times. Read carefully all the statements follow- 
ing this letter; at the end of the one which most nearly 
states the facts about your specimen, you will again be 
directed by a letter to another part of the Key. Continue 
this process till, instead of a letter, there is‘a number and 
name. The name is that of the genus, and forms the first 
part of the scientific name of the plant. Turn to the de- 
scriptive part of the book, where this number, in regular 
order, is found. Here descriptions of the species of the 
genus are given. If there are many species, another Key 
will lead to the species. While the illustrations are in- 
tended to represent characteristic specimens, too much 
dependence must not be placed upon them; the leaves 
even of the same plant vary considerably, and the differ- 
ent varieties, especially of a cultivated plant, vary widely. 
Read the whole description before deciding. 
The fractions beside the figures indicate the scale of the 
drawing as compared with the natural size of the part: 
1 indicates natural size; 2, that the drawing is twice the 
length of the object; 4, is one fourth the length, etc. 
In the description of leaves the dimensions given refer 
to the blade. 
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