INTRODUCTION. 



The notion of classing species according to the likeness they 

 bear to each other, which is the foundation of the Natural System, must 

 have originated with the first attempts of man to reduce natural his- 

 tory to a science. When our forefathers spoke of "grass, and herbs 

 yielding seed, and fruit trees yielding fruit, of moving creatures that 

 have life in the water, of fowl that fly above the earth, and cattle and 

 creeping thing," they employed the very same principles of arrange- 

 ment which are now in use, — rudely sketched, indeed, but not 

 more so than the imperfection of knowledge rendered unavoidable. 

 At that time no means existed of appreciating the value of minute 

 or hidden organs, the functions or even existence of which were 

 unknown ; but objects were collected into groups, characterised 

 by common, external, and obvious signs. From such principles no 

 naturalists except botanists have deviated ; no one has thought of 

 first combining under the name of animal kingdom quadrupeds and 

 birds, insects and fishes, reptiles and mollusca, and then of subdividing 

 them by the aid of a few arbitrary signs, in such a way that a portion 

 of each should be found in every group — quadrupeds among birds 

 and fishes, reptiles amongst insects and mammalia ; but each great 

 natural group has been confined within its own proper limits. 

 Botany alone, of all the branches of natural history, has been treated 

 otherwise ; and this in modern times. 



The first writers who acknowledged any system departed in no 

 degree from what they considered a classification of plants according 

 to their general resemblances. Theophrastus has his water-plants 

 and parasites, pot-herbs and forest trees, and corn-plants ; Dios- 

 corides, aromatics and gum-bearing plants, eatable vegetables and 

 corn-herbs; and the successors, imitators, and copiers of those 

 writers, retained the same kind of arrangement for many ages. 



At last, in 1570, a Fleming, of the name of Lobel, improved the 

 vulgar modes of distinction, by taking into account characters of a 

 more definite nature than those which had been employed by his 

 predecessors; and thus was laid the foundation of the modern 

 accurate mode of studying vegetation. To this author succeeded 

 many others, who, while they disagreed upon the value to be 

 ascribed to the small number of modifications of structure with 



