OKGAXS OF EEPEODrCTION. 291 



literation of parts, as the ovary ripens. Thus the ovary of the 



Oak, and Hazel, consists of three cells, each of which contains 



F' fi47 ^^^ ovules, but the fruit has only one cell 



^* ' and one seed, so that in the course of develop- 



^_-^^ ment five ovules and one cell have become 



\^'^K\ f1 obliterated. In the Birch we have an ovary 



^' '""'"' -\'i "^^^ ^^° cells, containing one ovule in each, 



but the fruit is one-celled and one-seeded, so 



that here one cell and ovule have become 



obliterated. In the Ash, Horse-chestnut, 



Elm, and many other plants, similar changes 



are produced in the ovary by the abortion or 



obliteration of certain parts. 



3rd. Other changes are produced in the 

 ''^uie^strawberry' ovary as it proceeds to maturity, in conse- 

 quence of the alteration of parts, as, for in- 

 stance, a great development of succulent parenchj-ma. Thus, 

 as already noticed, the thalamus of the Strawberiy {fig. 647) 

 becomes enlarged and siicculent, and forms what is commonly 

 termed the fruit, but the real fruit consists of the small dry 

 carpels which are scattered over its surface. The pulp of the 

 Guava, Gooseberry, Tomato, &e., in which the seeds are im- 

 bedded, appears to be produced from the placentas ; and that of 

 the Orange is of a similar nature. 



From the above examples it will be evident, that although the 

 fruit consists essentially of the mature ovary, yet that in the 

 progress of the latter organ towards maturity, it becomes fre- 

 quently much altered from its original structure, so that in 

 order to have a clear idea of the nature of the fruit, it is im- 

 portant to examine that of the ovary, and trace its develop- 

 ment up to the fruit. 



Genebal Chaeactees of the Feiht. — The structure of the 

 fruit resembling in all important particulars that of the ovary, 

 the modifications which it presents, as to composition, position, 

 &c., are described by similar terms. Thus we may have simple 

 and compoimd fruits, as also apocarpous and sy7icaipous ones. 

 Simple fruits, like simple ovaries, 2ixe novm-dWy imilocuhr; while 

 a compound fruit may have one or more cells, according as the 

 dissepiments are absent or present, and the nimiber of cells is 

 indicated by similar terms to those used when speaking of the 

 compound ovary. 



The frmt, again, is described as superior or inferior, in the 

 same sense as these terms are used in speaking of the ovary, 

 Thus a fruit is inferior, when it is formed from an inferior ovary, 

 in which case the calyx necessarily enters into its composition, 

 as in the Melon, Apple, Pear, and Quince {fig. 457) ; or it is su- 

 perior, as in the Poppy {fig. 426), and Pea {fig, 654), when the 

 ovary is superior, and the cal}^ non-adherent. 



