‘HOW TO USE THE KEY AND FLORA 
In order to determine an unknown species, the student is 
first to make a careful examination of the plant in hand. 
After noting in a general way the appearance of the root, 
stem, and leaf, including a cross-section of the stem, he 
should study the number, coherence, and adnation of the 
parts of the flower, then make and draw a cross-section and 
a lengthwise section of it. Irregularities in calyx or corolla, 
peculiarities in the shape, structure, or operation of the essen- 
tial organs, such, for instance, as anthers discharging through 
chinks in the end, should be noted. 
Next, the inquirer should look carefully through the Key 
to the families. He is first to decide whether the plant in 
question is a Gymnosperm or an Angiosperm; if not a conif- 
erous tree or shrub, it will of course belong to the latter 
division. He is then to settle the question whether it is a 
Monocotyledon or a Dicotyledon; then under what division of 
the group the plant comes; and, finally, to decide upon its 
family. | 
Turning now to the page at which the family is described, 
a rapid inspection of the characteristics of the genera will 
make it evident to which one the species under examination 
belongs. It may not infrequently prove that none of the 
genera described agree with the plant studied, and in that 
case the student must either consult a larger flora or rest 
satisfied with having determined the family to which his 
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