689 



THE FIBRO-VASCULAR SYSTEM OF THE QUINCE 

 FRUIT COMPARED WITH THAT OF THE APPLE 

 AND PEAR. 



By D. McAlpine, Corresponding Member. 



( Plates Ixxi.-lxxiii. ) . 



Tlie (juiiice agrees with the apple and pear in having five carpels, 

 but, in the cavity of each, there are two rows of ovules, instead of 

 merely two ovules in each chamber ( Fig. 4). After fertilisation, 

 the ovules become the well-known pips or seeds, while the walls of 

 the ovaries assume a leathery texture, and the whole represents the 

 "core." In the seed-coat of the quince, the cellulose becomes con- 

 verted into mucilage, which is said to serve the purpose of attach- 

 ing the seeds to the soil. The flask-like thickened floral axis be- 

 comes the succulent portion of the ripening quince. 



The vascular system of the quince will now be considered, and 

 it will be found to agree, in the main, with that already described 

 in connection with the apple and pear. 



According to De Candolle, in his Origin of Cultivated Flanta, "tlie 

 quince is a fruit which has been little modified by cultivation ; it is 

 harsh and acid when fresh, as in the time of the ancient Greeks." 

 The reduction of the number of seeds in the fruit of the apple and 

 pear, as compared with that of the quince, may be due to this very 

 fact of cultivation and selection applied to them, having induced a 

 more succulent ,and more palatable fleshy portion. The more 

 attractive the fruit becomes to animals and birds feeding upon it, 

 the more certainly will the seeds be widely distributed and de- 

 posited under conditions favourable to their germination. A 

 fewer number of seeds will thus suffice for the propagation of the 

 species, and even in tlie apple and pear, not only is there fre- 

 quently but one mature seed in each carpel, but there are ''seedless" 

 apples in which they have become aborted altogether. 



In some of the Natural Orders of plants, this reduction in the 

 number of seeds concurrently with the enhanced attractiveness of 



