108 TRANSACTIONS. NATURAL HISTORY SOCIETY OK GLASGOW. 



seeds may become dispersed. It is more probable, 

 however, that the green variety is a product of 

 cultivation which could not continue to maintain 

 itself in a wild state. 



Nature commonly avoids what is superfluous. 

 Accordingly w^e find that in many instances only 

 the exposed side of the fruit is brilliantly coloured, 

 the concealed surface retaining its green colour. A 

 peculiarity noticed in the rasp and some others is 

 that the fruit, partially hidden by the leaves, can 

 be seen more readily by a person standing at some 

 distance from the bush than when close beside it. 

 The intention seems to be to discourage birds from 

 settling on the plant and devouring its fruits in 

 quantity on the spot. This peculiarity compels a 

 bird to make more numerous journeys and secures 

 wider distribution. Further, when the bird is under 

 the necessity of flying to a neighbouring tree to 

 consvime the fruit it has got, or to make a survey 

 in search of more, the seeds will stand a better 

 chance of being delivered in localities favourable to 

 development — that is, in situations where birds are 

 in the habit of perching, such as thickets and shaded 

 plantations, corresponding to the habitat of the 

 rasp and similiar plants. Wind-carried seeds, unless 

 of minute size, would have very little chance of 

 penetrating such sheltered situations. But the 

 smaller a seed is, the more scanty the stock of 

 nourishment it can afford for the development of 

 the embryo during germination. This, to plants 

 which affect a shady habitat, w^ould be a decided 

 disadvantage, and therefore the mass of the seed 

 cannot w'ith safety be reduced below a certain limit. 



Succulent coloured fruits are especially character- 

 istic of the order Rosaceae to which many of our 

 cultivated fruits belong, such as the apple, pear, 

 medlar, quince, peach, plum, cherry, rasp, strawberry, 

 etc. It is somewhat remarkable that while the 

 fruits of this order are very highly specialised, the 

 flowers belong to a comparatively simple type, 



