ORGANS OF REPRODUCTION. 297 



are fresh in our memories. Such an arrangement has, also, 

 the further advantage of enabling us to describe the seed imme- 

 diately after the ovule, as these two organs are, in like manner, 

 only different conditions of one body. 



Nature of the Fruit. — After the process of fertilization has 

 been effected, important changes take place in the pistil and 

 surrounding organs of tlie flower, the result of which is the 

 formation of the fruit. The fruit consists essentially of the 

 mature ovary or pistil, containing the ripened ovules or seeds. 

 Although the fruit may thus be described as consisting essen- 

 tially of the mature pistil, other i^arts of the flower are also 

 fi-equently present, and assist in its composition. Thus in those 

 cases where the calyx is adherent to the ovary, as in the Apple, 

 Pear, Melon, Gooseberr}-, &c., that organ necessarily forms a 

 part of the fruit ; in the Eose the concave thalamus, which 

 bears the carpels on its inner surface, becomes a portion of the 

 fruit ; in the Strawberry, again, the fi'uit consists of the succu- 

 lent hemispherical thalamus, bearing the carpels on its convex 

 surface ; in the Acorn, Hazel-nut, Filbert, &c., it consists of 

 pistil, calyx, and bracts, combined together; while in the Pine- 

 apple {Jig. 706, 2), it is composed of the ovaries, floral enve- 

 lopes, and bracts of several flowers; in the Fig also {fig. 383), 

 ■we have a finiit formed of a number of separate flowers enclosed 

 in a fleshy receptacle. These examples, and a number of others 

 might have been alluded to, will show, that although the fruit 

 consists essentially of the ovary enclosing the ripe seeds, yet 

 the term is also apphed to whatever is combined with it, so as 

 to form a covering to the seeds. 



Changes produced in the Ovary in the course of its Develop- 

 ment. — The fruit being essentially the ovary in a mature state, 

 it should correspond with it in stmcture. This is the case 

 generally, and we find the fruit therefoi'e consisting of the 

 same parts or organs as the ovary, only in a modified condition; 

 thus, the walls of the ovary commonly alter in textm-e, and 

 either become dry, membranous, coriaceous, woody, &c. ; or, on 

 the contrary, more or less pulpy, fleshy, &c. 



At other times more important changes take place during the 

 ripening of the ovary, which disguise the real structure of the 

 fruit. These changes, either arise from the addition, or abortion, 

 or obliteration of parts. Thus, 1st. The addition of parts is 

 commonly produced by the formation of the spurious dissepi- 

 ments already alluded to. In the Datura Stramonium, for in- 

 stance, we have a two-celled ovary converted into an imperfectly 

 four-celled fruit, by the formation of a spurious vertical dissepi- 

 ment (figs. 601 and 602); this dissepiment appears to be formed 

 by the projection of the placentas on the two sides, which meet, 

 and become united to corresponding projections from the dorsal su- 

 tures. In the Cassia Fistula, again {fig. 599), and some other fruits 



