274 NATURAL SYSTEM OF CLASSIFICATION 



Emily. Let me see whether I can make out this gen- 

 ealogical table of plants. 



The three grand divisions give birth to 250 families. 

 These 250 families produce 5000 genera. 

 And the 5000 genera, 60,000 species. 



Mrs. B. The species, in their turn, give rise to races, 

 varieties and variations; but we shall not enter upon these 

 subdivisions at present, as they are the result of an artifi- 

 cial, rather than of a natural, mode of propagation ; and, 

 indeed, their numbers are both too great and too variable 

 to be reckoned in a table of classification. There are, 

 for instance, no less than fifteen hundred varieties of the 

 vine, and five hundred of the pear-tree : it is true that 

 other plants do not afford so great a number. 



Caroline. If they did, you might almost as well un- 

 dertake to count the individual plants as to number them. 

 But do not the number of species also increase by the dis- 

 covery of new plants ? 



Mrs. B. No doubt they do. Since the death of Lin- 

 naeus, about fifty thousand new species have been dis- 

 covered, making, on an average, one thousand species 

 every year. 



The numbers, therefore, which I have given you, are in- 

 tended only to enable you to form a general idea of the 

 present state of the vegetable kingdom ; but they cannot 

 be considered as permanent. 



This explanation will, I hope, enable you to under- 

 stand the basis of the natural classification, the details of 

 which can be acquired only by study and practice. 



Caroline. But how can we study this system, since 

 the English botanists follow that of Linnaeus ? 



Mrs. B. Generally they do, but not exclusively. We 

 already possess two excellent English works : the one 

 called the Flora Scotica, by Mr. Hooker, in which the 

 plants are classed both according to the system of Lin- 



1478. What is the genealogical table of plants, as she calls it, which 

 Emily makes outl 1479. What further divisions are there in the 

 vegetable kingdom 1 1480. How many varieties of the vine and pear 

 tree are there! 1481. Since the death of Linnaeus, how many new 

 species of plants have been discovered'? 1482. What is said of the 

 number given in this work! 1483. Of the Flora Scotica! 



