308 DARWINISM chap. 



than as regards conspicuousness, hence a tendency to any 

 decided colour has been preserved and accumulated as serving 

 to render the fruit easily visible among its surroundings of 

 leaves or herbage. Out of 134 fruit-bearing plants in 

 Mongredien's Trees and Shrubs, and Hooker's British Flora, 

 the fruits of no less than sixty-eight, or rather more than half, 

 are red, forty-five are black, fourteen yellow, and seven white. 

 The great prevalence of red fruits is almost certainly due to 

 their greater conspicuousness having favoured their dispersal, 

 though it may also have arisen in part from the chemical 

 changes of chlorophyll during ripening and decay producing 

 red tints as in many fading leaves. Yet the comparative 

 scarcity of yellow in fruits, while it is the most common tint 

 of fading leaves, is against this supposition. 



There are, however, a few instances of coloured fruits which 

 do not seem to be intended to be eaten ; such are the colo- 

 cynth plant (Cucumis colocynthus), Avhich has a beautiful fruit 

 the size and colour of an orange, but nauseous beyond descrip- 

 tion to the taste. It has a hard rind, and may perhaps be dis- 

 persed by being blown along the ground, the colour being an 

 adventitious product ; but it is quite possible, notwithstanding 

 its repulsiveness to us, that it may be eaten by some animals. 

 With regard to the fruit of another plant, Calotropis 

 procera, there is less doubt, as it is dry and full of thin, 

 flat-winged seeds, with fine silky filaments, eminently adapted 

 for wind -dispersal; yet it is of a bright yellow colour, as 

 large as an apple, and therefore very conspicuous. Here, 

 therefore, we seem to have colour which is a mere by- 

 product of the organism and of no use to it; but such 

 cases are exceedingly rare, and this rarity, when compared 

 with the great abundance of cases in which there is an 

 obvious purpose in the colour, adds weight to the evidence 

 in favour of the theory of the attractive coloration of edible 

 fruits in order that birds and other animals may assist in 

 their dispersal. Both the above-named plants are natives of 

 Palestine and the adjacent arid countries.^ 



The Colours of Flowers. 

 Flowers are much more varied in their colours than fruits, 

 ^ Canon Tristram's Natural Histary of the Bible, pp. 483, 484. 



