OF CLASSIFICATION. 271 



progress can be made without labor and preseverance : 

 much yet remains to be done, but it is gratifying to have 

 a great end in view : it elevates the mind, and renders the 

 details of a science interesting. The difficulties that oc- 

 cur in classification arise, either from our not yet knowing 

 all the plants that exist, or from our limited faculties often 

 preventing our acquiring a competent knowledge, of the 

 nature and internal structure of their organs. Time may 

 overcome the former of these difficulties ; but the latter 

 will probably never be completely conquered. Sometimes, 

 for instance, the organs of plants which ought to be sym- 

 metrical, are not all developed ; at others, they are join- 

 ed together so that their number cannot be distinguished : 

 this we have called soldering. Sometimes they assume 

 unusual form and dimension : this is called degeneration 

 of the organs. These three causes, considered either col- 

 lectively or separately, often deceive botanists in regard 

 to the real nature of the vegetable organs, but, by dint of 

 observation, the truth is gradually brought to light. 



Emily. We should, no doubt, be incapable of under- 

 standing in detail the results of the principles you have 

 explained to us ; but cannot you give us some slight idea 

 of them ? 



Mrs. B. I will make the attempt, at least. You may 

 recollect learning the other day, that genera was compos- 

 ed of those species most nearly resembling each other. 

 Now, by means of the principles I have just laid down, 

 it was soon discovered, that in a certain number of genera 

 the organs of re-production were very analogous : it was 

 then ascertained, that the organs of nutrition of these 

 same genera, also bore a striking resemblance to each 

 other. These genera were then united, as it were, in a 

 group, and denominated a family. Thus the five thou- 

 sand genera form about two hundred and fifty families. 



Caroline. Families of plants, then, are nothing more 

 than a numerous collection of genera resembling each 



1460. What is needful for progress in botanical science 1 ? 1461. 

 From what arise the difficulties that occur in classification 1 ? 1462. 

 What is said of overcoming these difficulties'? 1463. What three 

 causes have often deceived botanists in regard to the nature of vegetable 

 organs'? 1464. What does Mrs. B. tell Emily she must recollect as 

 having been learnt'? 1465. By means of those principles what is soon 

 learntl 1466. To what number of genera, and of families are plants 

 reduced! 



