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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