VARIETIES. 79 



has borne them of a bhie or red colour may pro- 

 duce seeds the plants arising from which may bear 

 white flowers. 



Thus, although the flowers of the Woody 

 Nightshade, Harebell, and Periwinkle, are com- 

 monly blue, yet they are occasionally white, 

 although of the same species ; and white varieties 

 also occur of the lesser Centaury, (Chironia) 

 which is more usually red, and of the Wild Mar- 

 joram. 



The leaves also, although in most cases 

 affording beautiful specific characters, are yet fre- 

 quently liable, in the same species, to remarkable 

 variations : thus in the Ivy growing near the 

 Tavistock tunnel, the leaves are linear, and ex- 

 ceedingly long ; a change in the character of the 

 plant attributable to the strong current of air 

 sweeping along the wall on which it is supported. 

 — Cultivation occasionally causes a plant, the 

 leaves of which are naturally flat, to bear them 

 curled. 



Many of the most valuable fruits, and most 

 beautiful of the cultivated flowers, are merely 

 varieties which have been produced by cultivation. 

 The seeds of such plants would not afford fruits 

 of the same flavour, nor flowers of the same hue. 

 They can only be propagated by buds, grafts. 



