TROPICAL NATURE 



details of these adaptations we must refer the reader to the 

 works of Darwin, Lubbock, Herman Miiller, 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 



x Trees and Shruts for English Plantations, by Augustus Mongredien. 

 Murray, 1870. 



