56 THE BOOK OF ROSES. 



yellowish white. This yellowish white, com- 

 bined with the blue-black of carbon, forms the 

 green colouring of the leaves ; but if neither 

 carbon, acids, nor alkalis operate upon the 

 yellowish white of the vegetable-tissue of the 

 corolla of a flower, it remains yellowish white ; 

 which the gardeners are pleased to name yellow, 

 as in the yellow China rose, the yellow Noisette. 

 But all these pseudo-yellow roses have more or 

 less a tinge of white, pink, or lilac: they are 

 never pure yellow. 



Pure yellow is therefore a specific character, 

 and invariable. 



OF THE SEPALS. The sepals are five in num- 

 ber; but a specific character has been attempted 

 through varieties in their form and position, 

 being divergent in some species, convergent 

 in others. This is not a safe distinction; for 

 in the Rosa spinosissima they are of the one 

 form, and in its hairy variety, the Pyrennean 

 rose, of another. They have also been defined 

 as perishable or permanent ; but in the white 

 rose they are perishable, and in its variety, the 

 Amelia, (of Vibert,) permanent; while in the 

 Bengal rose they are sometimes the one, some- 

 times the other. 



OF THE TUBE OF THE CALYX. All that has 

 been said of the uncertainty of form in the fruit, 

 may be applied to the tube of the calyx, or seed- 

 vessel, which is in fact the fruit before it attains 



