NATURAL HISTORY STUDIES 



or ovules have become real seeds. In most cases a 

 fruit may be described as the ripe seed-box, or as 

 a collection of ripe seed-boxes, with or without 

 extra parts, such as the fleshy top of the flower- 

 stalk or the remains of the calyx. In some cases, as 

 in common cereals, where a single seed fills the 

 seed-box, fruit and seed are almost identical, though 

 the scientific difference remains clear. 



In order to understand the different kinds of 

 fruits, we must also notice that the wall of the fruit 

 (the pericarp) often consists of several layers, very 

 different from one another. Thus in the familiar 

 case of a plum there is the firm outside skin (epicarp), 

 which keeps bacteria and moulds out until it gets 

 even a slight wound ; there is the fleshy pulp 

 (mesocarp), which is all loss to the parent plant, 

 but attracts the birds, which scatter the seeds ; and 

 there is the very hard "stone" (endocarp), which 

 effectively preserves the seed within a living 

 embryo from being digested in the bird's food- 

 canal, from being frost-bitten in the ground, from 

 premature sprouting, and from other risks. 



The use of the fruit is really to give the seeds a 

 good send-off in life ; but this requires looking into. 

 (1) The seed is an embryo plant with a legacy of 

 nutritive material ; it grows within the ovule from 

 a microscopic egg-cell fertilized by a pollen-grain ; 

 it is, for a time, a very delicate young life. One use 

 of the fruit is to protect the developing seed from 

 bad weather. (2) Even when the seeds are fully 

 formed and have got a good grip of life, there is need 

 for the fruit's protection, for instance, against small 



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