ITS STRUCTURE AND TRANSFORMATIONS. 321 



word is used by the botanist, things of very different structure or 

 of different degrees of complexity are confounded. These need to 

 be properly distinguished. For the present, we will consider the 

 fruit in the stricter sense, as consisting of the matured pistil alone, 

 whether simple or compound, either free or in combination with 

 any floral organs, such especially as the tube of the calyx, which, 

 being adnate to the ovary in the flower, is necessarily incorpo- 

 rated with the pericarp in fructification. 



585. The pericarp, being merely the matured pistil, should ac- 

 cord in structure with the latter, and contain no organs or parts 

 that do not exist in the fertilized ovary. Some alterations, how- 

 ever, often take place during the growth of the fruit, in conse- 

 quence of the abortion or obliteration of parts. Thus, the ovary of 

 the Oak (Fig. 1044) consists of three cells, with a pair of ovules in 

 each ; but the acorn, or ripened fruit, presents a single cell, filled 

 with a solitary seed. In this case, only one ovule is matured, and 

 two cells and five ovules are suppressed. The ovary of the Horse- 

 chestnut and Buckeye is similar in structure (Fig. 659 - 661), and 

 seldom ripens more than one or two seeds : but the abortive seeds 

 and cells may be detected in the ripe fruit. The ovary of the 

 Birch (Fig. 1053) is two-celled, with a single ovule in each cell : 

 the fruit is one-celled, with a solitary seed ; one of the ovules or 

 young seeds being uniformly abortive, while the other in enlarging 

 pushes the dissepiment to one side, so as gradually to close the 

 empty cell (as in Fig. 1056). The Elm presents a similar case 

 (Fig. 1013, 1014) ; and such instances of suppression in the fruit 

 of parts actually extant in the ovary are not uncommon. 



586. On the other hand, the fruit sometimes exhibits more cells 

 than the pistil ; as in the two-celled ovary of Datura Stramonium, 

 which soon becomes spuriously four-celled by the projection of the 

 placentae on each side, so as to reach and cohere with a projection 

 of the dorsal suture on each side. So, also, many legumes are 

 divided transversely into several cells, although the ovary was one- 

 celled with a continuous cavity in the flower. 



587. Ripciling, The growing fruit attracts its food from sur- 

 rounding parts in the same manner as leaves. When the pericarp 

 preserves its green color and leaf-like texture (as in the Pea, &c.), 

 it is furnished with stomates, and acts upon the air like ordinary 

 leaves. Those which become fleshy or juicy acquire that condi- 

 tion by the accumulation of elaborated sap in their tissue ; where 



