C i. XVII.] CLASSIFICATION. 103 



touch. Some vegetables, however, seem to have a kind of sen 

 sibility like that derived from the organs of touch in aninii Is ; 

 they tremble and shrink back upon coming in contact w th 

 other substances ; some turn themselves round to the sun, as if 

 enjoying its rays. There is a mystery in these circumstances 

 which we cannot penetrate ; and it is not yet fully known at 

 what point in the scale of existence animal life ends, and vege- 

 table life commences. 



CHAPTER XVII. 



General Principles of Classification Natural Families of 



Plants. 



420. LET us now imagine the whole vegetable kingdom, 

 compri-ing innumerable millions of individual plants, to be 

 spread out before a botanist. Could he, in the course of the 

 longest life, number each blade of grass, each little moss, each 

 =hrub, or even each tree ? If he could not even count them, 



j 



much less could he give each one a separate name and descrip- 

 tion. But he does not need to name them separately, for ne 

 sees that nature has arranged them into sorts or kinds. 



431. If you were sent into the fields to gather flowers of a 

 similar kind, you would need no book to direct you to put into 

 one parcel, all the red clover blossoms, and into another, the 

 white cJnrer ; while the dandelions would form another group. 

 These all constitute different species. Nature would also teach 

 you that the red and white clover, although differing from each 

 other in c ome particulars, yet bear a strong resemblance. 



432. By placing species together you form a genus, and to 

 this srenns you refer all the different kinds of clover. When 

 you see red, damask, and cmnamon roses, you perceive they 

 all have such strong marks of resemblance as to entitle them 

 to be placed together in one genus. 



433. But yet you know that the seed of a damask rose would 

 never produce a red rose. One species of plants can never 

 produce another species, however near may be their resem- 

 blance. 



434. The whole number of species of plants which have 



430. !? it necessary for the botanist to give a particular name to 

 every plant'? 



431. Po you need a book to teach you to put flowers of the same 

 sort together? 



43:2. How is a genus, formed? 



433. P'les one species ever produce plants of another specie^'? 



434. What number of species have been discovered 1 ? 



