54 THE BOOK OF ROSES. 



OF THE STAMENS. The stamens have been 

 attempted as a ground-work for classification ; 

 but abandoned as affording only vague and 

 variable indications. 



OF THE PETALS. Neither can the petals be 

 accepted. In point of number, every rose, in 

 its natural state, has five ; which may be aug- 

 mented by culture, pruning, and even age. In 

 form they are equally uncertain, varying beyond 

 calculation in varieties of the same species. In 

 length, they are sometimes shorter than the 

 sepals, as in the Carolina rose; while in its va- 

 riety, the Virginian rose, they are as long. In 

 various cluster roses they are longer in the cen- 

 tral rose than in those which surround it. The 

 colour of the petals constitutes their most im- 

 portant specific character ; and this point de- 

 mands consideration. 



Vegetables contain certain colouring-matter, 

 inseparable from their substance ; as the yellow 

 of woad, the red of madder. When this colour- 

 ing matter becomes exposed to the action of 

 acid, which contact is most frequently produced 

 by the influence of light, a new colour is formed 

 by the combination. The red colour of fruit is 

 supposed to arise from the action of an "acid 

 upon blue colouring-matter; and almost all 

 purple, red, and blue flowers derive their colour 

 from an acid analogous to that of fruit. 



Red, blue, and white are readily varied from 

 one to the other, in substances of a similar 



