398 TROPICAL NATURE 



very minute and are carried abroad by the wind, or they are 

 violently expelled and scattered by the bursting of the con- 

 taining capsules. Others are downy or winged, and are 

 carried long distances by the gentlest breeze, or they are 

 hooked and stick to the fur of animals. But there is a large 

 class of seeds which cannot be dispersed in either of these 

 ways, and they are mostly contained in eatable fruits. These 

 fruits are devoured by birds or beasts, and the hard seeds 

 pass through their stomachs undigested, and, owing probably 

 to the gentle heat and moisture to which they have been sub- 

 jected, in a condition highly favourable for germination. The 

 dry fruits or capsules containing the first two classes of seeds 

 are rarely, if ever, conspicuously coloured, whereas the eatable 

 fruits almost invariably acquire a bright colour as they ripen, 

 while at the same time they become soft and often full of 

 agreeable juices. Our red haws and hips, our black elder- 

 berries, our blue sloes and whortleberries, our white mistletoe 

 and snowberry, and our orange sea-buckthorn, are examples 

 of the colour-sign of edibility ; and in every part of the world 

 the same phenomenon is found. Many such fruits are poison- 

 ous to man and to some animals, but they are harmless to 

 others ; and there is probably nowhere a brightly coloured 

 pulpy fruit which does not serve as food for some species of 

 bird or mammal. 



Protective Colours of Fruits 



The nuts and other hard fruits of large forest-trees, though 

 often greedily eaten by animals, are not rendered attractive 

 to them by colour, because they are not intended to be eaten. 

 This is evident, for the part eaten in these cases is the seed 

 itself, the destruction of which must certainly be injurious to 

 the species. Mr. Grant Allen, in his ingenious work on 

 Physiological Esthetics, well observes that the colours of all 

 such fruits are protective green when on the tree, and thus 

 hardly visible among the foliage, but turning brown as they 

 ripen and fall on the ground, as filberts, chestnuts, walnuts, 

 beechnuts, and many others. It is also to be noted that 

 many of these are specially though imperfectly protected, 

 some by a prickly coat as in the chestnuts, or by a nauseous 

 covering as in the walnut ; and the reason why the protection 



