COLOURS OF PLANTS. 231 



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. The red Martagon lily has been 

 observed by Mr. Herman Miiller to be fertilized by the 

 humming-bird hawk moth, which flies in the morning 

 and afternoon when the colours of this flower, exposed 

 to the nearly horizontal rays of the sun, glow 

 with brilliancy, and when it also becomes very sweet- 

 scented. 



Attractive grouping of Flowers. To the same need of 

 conspicuousness the combination of so many individually 

 small flowers into heads and bunches is probably due, 

 producing such broad masses as those of the elder, the 

 guelder-rose, and most of the Umbelliferse, or such 

 elegant bunches as those of the lilac, laburnum, horse 

 chestnut, and wistaria. In other cases minute flowers 

 are gathered into dense heads, as with Globularia, 

 Jasione, clover, and all the Compositae ; and among the 

 latter the outer flowers are often developed into a ray, as 

 in the sunflowers, the daisies, and the asters, forming a 

 starlike compound flower, which is itself often produced 

 in immense profusion. 



1 Trees and Shrubs for English Plantations, by Augustus Mongredien. 

 Murray, 1870. 



