224 ON FRUIT. 



After the flower has performed its office of fructifying 

 the seed ; the petals, and every organ which is not des- 

 tined to become a part of the fruit, wither and fall off. 

 In the mean time, the ovary grows, and gradually as- 

 sumes the appearance of a fruit. 



Emily. Is the fruit, then, formed from the original 

 little leaf which so carefully guarded the seed when the 

 flower was in blossom, and which you called a carpel ? 



Mrs. B. Yes ; when it assumes the form of fruit, it is 

 frequently called by botanists pericarp. 



Caroline. But I suppose it retains the name of seed- 

 vessel, since it contains the seed in the fruit as well as 

 in the flower ? 



Mrs. B. Certainly. Now let us take, for example, 

 one in which the form of the original leaf is not wholly 

 obliterated this pod of a pea, for instance : you may 

 plainly see that it consists of a leaf doubled over the 

 seeds, with its edges united. 



Emily. This pod, which is very young, is almost flat ; 

 but here is a larger one, which is become convex, in or- 

 der to make room for the growth of the peas ; and I per- 

 ceive that the older it grows, the more it loses the form 

 and appearance of a leaf. 



Caroline. In shelling peas, I have observed that the 

 pod readily opens where the edges of the leaf have been 

 soldered together ; but if you attempt to sever the pod at 

 the opposite seam, which I suppose forms the midrib of 

 the leaf, it is much more difficult. 



Mrs. B. You are mistaken there, my dear ; for, in 

 shelling peas, the pod is opened by splitting asunder the 

 midrib of the leaf. When the pod is ripe, this rib opens 

 of itself, and the opposite suture or seam, formed by the 

 soldering of the edges of the leaf, also gives way ; so that 

 the pod is separated into two halves or valves, and the 

 seeds detach themselves and fall to the ground. This is 

 a natural mode of opening, for the purpose of shedding 

 their seed, which is common to a great number of peri- 

 carps : it is called dehiscence. 



1224. How is the change described'? 1225. What is the pericarp 1 

 1226. For what purpose does Mrs. B. examine the pod of a peal 

 1227. What mistake does Caroline make concerning ill 1228. How 

 does Mrs. B. explain her mistake 1 1229. What is dehiscence^ 



