96 ASSOCIATION OF ORGANISMS THE WEB OF LIFE 



in which is contained a dormant plantlet, that has resulted from 

 the fertilization of an egg-cell. The fertilizing process stimulates 

 the growth of various parts external to the ovules, leading to the 

 production of what may broadly be called a " fruit ", which for 

 our present purpose may be considered as a seed-carrier. A 

 cherry or plum, for example, is a fruit, within which is a single 

 seed the " stone ". A long account of the different kinds of 

 fruit would be out of place here, but it .may be well to add that 

 many are hard and dry, e.g. hazel-nuts (of which the " kernels " 

 are the seeds), poppy- " heads ", and the so-called " seeds" of Sun- 

 flower or Carrot. 



The dispersal of seeds in many plants results from the fact 

 that a considerable number of animals are fruit-eaters. And in 

 such cases the seeds being protected by hard coats often escape 

 digestion. It would appear that the attractive colours and 

 palatable qualities of numerous fruits have been evolved with 

 direct reference to this. While still unripe such fruits are incon- 

 spicuous and more or less nauseous, but become extremely 

 conspicuous by the time they are ready for consumption, thus 

 advertising their desirable properties as articles of diet. Though 

 monkeys and other fruit -eating mammals no doubt largely assist 

 in plant dispersal, birds seem to play a more important part in 

 the matter. Kerner made a large number of experiments which 

 tend to prove this. He found, for example, that the hard-coated 

 seeds of stone-fruits and berries passed quite uninjured through 

 the bodies of ravens and jackdaws; also that the blackbird, song- 

 thrush, rock-thrush, and robin, which eagerly devour fleshy fruits, 

 throw up the seeds if these are large, as in Barberry and Privet 

 The fate of small seeds swallowed by the last four birds is thus 

 described by him (in The Natural History of Plants]'. " Of the 

 fruits and seeds which passed through the intestine of one or 

 other of these birds, 75 per cent germinated in the case of the 

 blackbird, 85 per cent in the case of the thrush, 88 per cent in 

 the case of the rock-thrush, and 80 per cent in the case of the 

 robin. . . . From these experiments it is evident that the dispersal 

 of edible fruits through the agency of thrushes and blackbirds is 

 not, as was formerly supposed, an exceptional phenomenon obtain- 

 ing in the mistletoe only, but one that may take place in the case 

 of many other plants, and other observations prove that, as a 

 matter of fact, it does take place." 



