x INTRODUCTION. 



By the common practice of the schools, pupils often 

 " go through " the botanical text-books with only the most 

 incidental attention to the real objects of study. As there 

 is no training in observation, there can be no attempt at 

 the exercise of the reason and judgment of the learner 

 upon the results of observation. To attain this important 

 end, botany must be studied in its actual objects. The 

 characters of plants must become familiarly known by the 

 detailed and repeated examination and accurate descrip- 

 tion of large numbers of plants. The pupil must proceed 

 step by step in this preliminary work digesting his ob- 

 servations, and making the facts his own. From the be- 

 ginning he will be engaged in comparing his observations, 

 and reasoning upon his facts. As he extends his knowl- 

 edge, the work of comparison and grouping calls for a 

 higher exercise of thought. In the final classification of 

 plants, problems of increasing complexity arise. Plants 

 are to be placed in groups subordinate to each other, 

 when judged by masses of resemblances, by likenesses, 

 and differences of unequal values, which involve the exer- 

 cise of the best powers of the mind. 



That the habit of systematic arrangement, in which 

 the study of botanical classification affords so admirable 

 a training, is equally valuable in methodizing all the re- 

 sults of thought, is testified to as a result of his own expe- 

 rience by that eminent authority, Mr. John Stuart Mill. 

 He was a regular field botanist, and cultivated the subject 

 with a view to its important mental advantages. In the 

 second volume of his " System of Logic "Mr. Mill says : 



" Although the scientific arrangements of organic na- 

 ture afford as yet the only complete example of the true 

 principles of rational classification, whether as to the 

 formation of groups or of series, these principles are ap- 

 plicable to all cases in which mankind are called upon to 

 bring the various parts of any extensive subject into men- 

 tal co-ordination. They are as much to the point when 



