254 ON THE CLASSIFICATION 



Caroline. Why do you consider the relative size of 

 organs of more importance than their absolute size? 



Emily. That appears to me quite clear. If a plant 

 grows in a rich soil, all its pa'rts will be larger than a sim- 

 ilar plant growing in a meagre soil ; yet the plants will 

 be of the same nature. But if the stamens of a plant be 

 twice as long as its petals, it will certainly be of a differ- 

 ent nature from a plant of which the stamens are shorter 

 than the petals ; and, were the two plants well or ill fed, 

 their proportion or relative size would not be altered. 



Caroline. You say, Mrs. B., that, the number of or- 

 gans of a plant is admitted as one of the characters of 

 genera ; but I think, I remember having seen, on the 

 same syringa shrub, flowers, some of which had four, and 

 others five petals. 



Mrs. B. Your observation is correct ; and, in order 

 to obviate this difficulty, you must be guided by the same 

 rule, in regard to number, which Emily has just pointed 

 out with regard to size. Thus, for example, the pink 

 has twice as many stamens as petals : this character 

 never varies, unless in some peculiar cases of monstrosi- 

 ty which derange the whole economy of the plant. 



With regard to the absolute number of organs, that is 

 to say, whether a plant has four or five petals, eight or 

 ten stamens, is a circumstance attended with much more 

 uncertainty ; it may, however, be used as a character in 

 classification, provided it be done with caution, and in 

 cases only, in which experience has shown, that the va- 

 riations are inconsiderable. Botanists know, for instance, 

 that the greater the number of organs, the more liable 

 that number is to vary. This is a law which prevails 

 throughout all Nature. 



Emily. It is evident that the number of our fingers 

 varies less than that of our teeth, and the latter less than 

 that of our hair. 



Mrs. B. These general rules will, I hope, make you 

 understand how botanists have been enabled, gradually 

 to draw a more accurate line of demarcation in circum- 



1382. What appears quite clear to Emily* 1383. What does 

 Caroline mention of the syringa shrubl 1384. In order to obviate 

 this difficulty, by what must one be guided; and what example is given! 

 1385. What is said of the absolute number of organs in plants'? 

 What law relating to this subject is said to prevail throughout all na- 

 ture'? 1387. How have Botanists been benefited by the general rules 

 above given 1 



