366 THE FRUIT 



becomes differentiated into three layers the " skin," 

 the " flesh " and the " stone " : the " kernel " is the 

 seed. 



In the rose the flower is perigynous as in the cherry, 

 but there are many separate carpels, each containing 

 a single seed, within the urn-shaped receptacle, beyond 

 the mouth of which the stigmas proj ect. In the develop- 

 ment of the fruit the carpels themselves do not increase 

 very much in size, but the wall of the receptacle grows 

 and becomes fleshy, forming the well-known red " hip " 

 or rose fruit. 



In the apple and pear the receptacle in the flower 

 has very much the same shape as in the rose, though it 

 is less elongated ; but it is fused with the walls of the 

 five carpels enclosed within it. Both receptacle and 

 ovaries increase greatly in size after fertilisation, the 

 former becoming the " flesh " of the apple and the 

 latter the " core." The " pips " are the seeds. A 

 cross-section of an apple shows that the ovaries are 

 separate from one another as they are in the rose, though 

 they are embedded in the flesh of the receptacle. 



In the strawberry the receptacle, instead of being 

 hollow and covering the carpels, is convex, and in the 

 development of the fruit it swells and becomes succulent 

 separating the one-seeded carpels (" pips ") by its 

 great increase in surface, over which the carpels are 

 distributed. The style of each carpel may still be 

 seen attached to each " pip." The cinquefoils, which 

 are close allies of the strawberry, have exactly similar 

 carpels, but the receptacle does not become fleshy, 

 so that the carpels are still crowded together in fruit. 



In the mulberry, which is derived from an inflorescence 

 (group of flowers), it is the perianth leaves (two pairs) 

 which become succulent, enclosing the pip-like ovary. 



