246 STUDY OF COMMON PLANTS. 



have learned to distinguish species, genera, families, orders, 

 and classes ; but these are simply expressions of so many 

 different degrees of relationship that pass insensibly into 

 each other, and call for the exercise of clear judgment, 

 profound knowledge, and critical attention to details on 

 the part of those who attempt to recognize and define 

 them. 1 



This is a conception widely different from that which 

 supposes " that species, and even genera, are like coin from 

 the mint, or bank-notes from the printing press, each with 

 its fixed marks and signature, which he that runs may 

 read, or the practiced eye infallibly determine," but "there 

 is grandeur in this view of life, with its several powers, 

 having been originally breathed by the Creator into a few 

 forms or into one ; and that, whilst this planet has gone 

 cycling on according to the fixed law of gravity, from so 

 simple a beginning, endless forms most beautiful and most 

 wonderful, have been and are being evolved." 2 



^ After some months of such training as is outlined in the preceding 

 exercises, the student should be prepared to take up with profit a study 

 of the flora of the region in which he lives. In this way, with an indefi- 

 nite amount of painstaking, independent, and long-continued work, he 

 will gradually become more familiar with the systematic grouping of 

 plants and accumulate for himself the evidence that more and more con- 

 firms the conclusion formulated above. 

 2 Darwin, Origin of Species, p. 429. 



