402 
TROPICAL NATURE 
Vi 
details of these adaptations we must refer the reader to the 
works of Darwin, Lubbock, Herman Muller, and others. We 
have here only to deal with the part played by colour, and 
by those floral structures in which colour is most displayed. 
Attractive Odours in Flowers 
The sweet odours of flowers, like their colours, seem 
to have been developed as an attraction or guide to insect 
fertilisers, and the two phenomena are often complementary 
to each other. Thus, many inconspicuous flowers, like the 
mignonette and the sweet -violet, can be distinguished by 
their odours before they attract the eye, and this may often 
prevent their being passed unnoticed ; while very showy 
flowers, and especially those with variegated or spotted petals, 
are seldom sweet. White, or very pale flowers, on the other 
hand, are often excessively sweet, as exemplified by the 
jasmine and clematis ; and many of these are only scented at 
night, as is strikingly the case with the night-smelling stock, 
our butterfly orchis (Habenaria chlorantha), the greenish- 
yellow Daphne pontica, and many others. These white 
flowers are mostly fertilised by night-flying moths, and those 
which reserve their odours for the evening probably escape 
the visits of diurnal insects, which would consume their 
nectar without effecting fertilisation. The absence of odour 
in showy flowers, and its preponderance among those that 
are white, may be shown to be a fact by an examination of 
the lists in Mr. Mongredien’s work on hardy trees and shrubs. 1 
He gives a list of about 160 species with showy flowers, and 
another list of sixty species with fragrant flowers ; but only 
twenty of these latter are included among the showy species, 
and these are almost all white flowered. Of the sixty species 
with fragrant flowers, more than forty are white, and a 
number of others have greenish, yellowish, or dusky and 
inconspicuous flowers. The relation of white flowers to 
nocturnal insects is also well shown by those which, like the 
evening primroses, only open their large white blossoms after 
sunset, while most of the yellow species remain open all day. 
The red Martagon lily has been observed by Mr. Herman 
1 Trees and Shrubs for English Plantations , by Augustus Mongredien. 
Murray, 1870. 
