546 
MORPHOLOGY. 
BOOK VI. 
With regard to colour, its infinite changes and metamor- 
phoses in almost every cultivated flower can be compared to 
nothing but the alterations caused in the plumage of birds 
or the hairs of animals by domestication. No cause has ever 
been assigned to these phenomena, neither has any attempt 
been made to determine the cause in plants. We are, how- 
ever, in possession of the knowledge of some of the laws 
under whicli change of colour is effected. A blue flower will 
change to white or red, but not to bright yellow ; a bright 
yellow flower will become white or red, but never blue. Thus 
the hyacintli, of which the primitive colour is blue, produces 
abundance of white and red varieties, but nothing that can be 
compared to bright yellow ; the yellow hyacinths, as they are 
called, being a sort of pale yellow ochre colour verging to 
green. Again, the ranunculus, which is originally of an 
intense yellow, sports into scarlet, red, purple, and almost any 
colour but blue. White flowers, which have a tendency to 
produce red, will never sport to blue, although they will to 
yellow ; the rose, for example, and Chrysanthemums. It is 
also probable that white flowers, with a tendency to produce 
blue, will not vary to yellow ; but of this I have no instance 
at hand. 
Smell varies in degree rather than in nature ; some plants, 
wliich are but slightly perfumed, as the common China rose, 
acquire a powerful fragrance when converted to the variety 
called "the sweet-scented;" but 1 am not acquainted with any 
case among flowers in which a positive difference of smell 
exists in two varieties of the same species. 
Metamorphoses of the fruit are very common, and administer 
largely to the wants of mankind. They consist of alteration 
in colour, size, flavour, smell, and structure. The wild blue 
sloe of our hedges has, in the course of ages, by successive 
domestication, been converted into the purple, white, and yel- 
low plums of our desserts. The wild crab is the original from 
which have sprung the many-coloured, Proteus-like variety of 
the apple ; some of which are destitute of smell, others scented 
like the pine-apple, and a few partaking of the perfume of the 
rose. In peas the parchment-like lining of the pod occa- 
