CHARACTERS USED IN CLASSIFICATION. 173 



But in the artificial orders, genera which may be very un- 

 like in other respects, are brought together, from the single 

 circumstance of their having the same number of stamens 

 and pistils. Thus, in the first order of the 8th class we have 

 the tulip and the bulrush, the lily of the valley and the sweet 

 flag. In the second order of the 5th class we have the beet 

 and the elm. You will at once perceive the striking disparity 

 between these plants, and that an arrangement, which thus 

 brings them together, is properly called an artificial method. 



Many families of plants possess a marked resemblance in 

 form and qualities, and appear evidently as distinct tribes. If 

 the whole of the vegetable kingdom could thus be distributed 

 into natural classes, the study of botany would be much sim- 

 plified ; but it has already been remarked that there are many 

 plants which cannot be thus arranged, and no principle has yet 

 been discovered for systematic arrangement which bears any 

 comparison to the Artificial System. This system is compar- 

 ed to a dictionary ; though by its use we do not at first find 

 the word for which we seek, and then learn its definition, as 

 we do in dictionaries of terms ; but we first learn some of the 

 characters of a plant, and by these as our guide, we proceed 

 to find the name. We are not however to rest after finding 

 the botanical name ; but having ascertained this, we can easily 

 find to what natural family a plant belongs, and thus ascertain 

 its habits, medicinal use, and other important particulars. Th$ 

 natural method may then be considered as the grammar of 

 botany ; between this and the artificial systenij the same rela- 

 tion exists, as between the grammar and dictionary of a lan- 

 guage ; both are necessary to science. 



As the subject of classification is so important to a knowledge 

 of botanical science, we will now consider the general princi- 

 ples on which it depends. 



Rules. 



1st. All botanical classification results from an examination 

 and comparison of plants. 



2d. Every organic distinction which establishes between indi- 

 viduals any resemblance, or any difference, is a character ; that 

 is, a sign, by which they may be known and distinguished. 



3d. The presence of an organ, its different modification and 

 its absence, are so many characters. 



4th. The presence of an organ furnishes positive characters, 

 its absence negative characters. 



Genera in the artificial orders brought together by having the same number 

 of stamens and pistils Artificial system of arrangement compared to a dic- 

 tionary First learn the characters, then the name The natural method con- 

 sidered as the grammar of botany Mention the first four rules which are 

 given for classification. 



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