NATURE OF OVULES. FORMATION OF FRUIT. 307 



rest, and of sending forth little granules which are to form new 

 plants, instead of adding to the number of cells in the parent 

 structure. Every cell of the Confervas, it will be recollected 

 (. 424), may be regarded as essentially a pollen-grain ; and 

 therefore the difference cannot be really so great as it appears. 

 Further, in regard to the ovules, the fact heretofore mentioned 

 (. 240) that certain leaves have the power of producing little 

 buds from their edges, becomes of great interest; for, if the 

 ovules could be regarded as at all analogous to buds, it is evident 

 that their situation on the edges of the carpellary leaf would 

 quite correspond with that of the buds of the 'BryopJiyllum^ or 

 of the Bog Orchis. And it has been proved by the occurrence 

 of some curious monstrosities, that this is a real analogy ; for a 

 seed-vessel of Mignionette has been known to bear a set of little 

 buds at the edges of its carpellary leaves, arranged just as the 

 ovules should have been. 



470. We have in the last place to consider the structure of 

 the Fruit, which is the mature or ripened ovary containing ferti- 

 lised seeds. This frequently differs remarkably from the ovary, 

 which the centre of the flower contained, both in its external 

 appearance, and in the arrangement of its interior. For example, 

 the Cherry, Plum, Almond, or other stone fruit, is formed by a 

 remarkable change in the substance of the carpellary leaf;, the 

 internal surface of this becomes hardened into the stone, whilst 

 the external remains as a thin cuticle or skin ; and the pulp of 

 the fruit is formed, by the increase of the parenchyma or fleshy 

 tissue of the leaf. Here each carpel originally contained several 

 ovules, but only one of them is usually developed. In the ovary 

 of the Chesnut, there are originally seven carpels or cells with 

 two ovules in each, whilst the ripe fruit consists of but one cell 

 and one seed ; so that no fewer than six cells and thirteen ovules 

 are suppressed, in order to enable a single ovule to grow and be 

 matured. It is not uncommon, however, to find two or even 

 three Chesnuts within a single shell, separated by slight parti- 

 tions. The fruit of the Orange, as formerly mentioned, consists 

 of the carpels, surrounded by the external coat of the ovarium ; 

 and having the space between their inner wall and the seeds they 



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