250' FRUIT OR MATURE PISTIL. 



raent of seeds seems to lead to a larger growth, and a greater succu- 

 lence of the fruit. 



522. In order to comprehend the structure of the fruit, it is of great 

 importance to study that of the ovary in the young state. It is in this 

 way only that the changes occurring in the progress of growth can be 

 determined. The fruit, like the ovary, may be formed of a single 

 carpel, or of several It may have one cell or cavity, then being uni- 

 locular (MWWS, one, and loculus, box or cavity) ; or many, multilocular 

 (multus, many), &c. The number and nature of the divisions depend 

 on the number of carpels, and the extent to which their edges are 

 folded inwards. The appearances presented by the ovary do not, how- 

 ever, always remain permanent in the fruit. Great changes are ob- 

 served to take place, not merely as regards the increased size of the 

 ovary, its softening and hardening, but also in its internal structure, 

 owing to the suppression, enlargement, or union of parts. In this way 

 the parts of the fruit often become unsymmetrical, that is, not equal to, 

 or some multiple of, the parts of the flower ; and at times they are 

 developed more in one direction than another, so as to assume an irre- 

 j gular appearance. In the Ash (fig. 437), an ovary with two 

 cells, each containing an ovule attached to a central placenta, 

 is changed into a unilocular fruit with one seed ; one ovule, 

 I, having become abortive, and the other, g, gradually extend- 

 ing until the septum is pushed to one side, becoming united 

 to the walls of the cell, and the placenta appearing to be parietal. 

 In the Oak and Hazel, an ovary with three cells, and two ovules 

 in each, changes into a one-celled fruit with one seed. Simi- 

 lar changes take place in the Horse-chestnut, in 

 which the remains of the abortive ovules are often 

 seen in the ripe fruit. In the Coco-nut, a trilocular 

 and triovular ovary is changed into a one-celled, 

 one-seeded fruit. This abortion may depend on the 

 pressure caused by the development of certain ovules, 

 or it may proceed from the influence of the pollen 

 not being communicated to all the ovules. Again, 

 by the growth of the placenta, or the folding inwards 

 of parts of the ovary, divisions may take place in the fruit which did not 

 exist in the ovary. In Pretrea Zanguebarica, a one-celled ovary is 

 changed into a four-celled fruit by the extension of the placenta. In 

 Cathartocarpus Fistula (fig. 395), a one-celled ovary is changed into a 

 fruit having each of its seeds in a separate cell, in consequence of spu- 

 rious dissepiments being produced in a horizontal manner from the inner 



