44 jRemarh on the fruit of the Natural Order CucurMacece. [July 



Pr. Arnott in the article Botany, Encyclop. Frit. Ed. 7, gives a dif- 

 ferent account of it, but still, it appears to me, far from a corrert one, 

 namely : — " A pepn or peponida is a fleshy inferior fruit, either indehiscent 

 or bursting irregularly, and consisting of about three carpels, each of which 

 is divided into tvro cells by its placentiferous margin, being so introflexed 

 as to react the dorsal suture. The sides of the carpel, and even some- 

 times the introflexed portion, usually become extremely thick and 

 fleshy, forming the great mass of the ripe fruit, so that by losing the 

 general character of dissepiments, they might almost be said to disap- 

 pear, and thus at first sight a pepo would be said to be, and has been 

 so described, a 1 -celled, fleshy, indehiscent fruit, with parietal placentas, 

 that send out sometimes false dissepiments towards the axis, as the 

 cucumber and gourd." 



This view, therefore, is essentially difi'erent from Dr. Lindley's, for, ac- 

 cording to Arnott the placentse are virtually central, not parietal. The 

 only difference between a pepo and an apple being, according to him, that 

 the placentiferous margins of the carpellary leaf are introflexed, and 

 extend outwards nearly to the parietes of the fruit, in place of remain- 

 ing in the axis. Lindley cn the other hand views a pepo simply as a 

 one-celled fruit with parietal placentae, the cavity being occasionally 

 divided into spurious cells by projections of the placentae. Neither are 

 altogether consonant with appearances, though that of Arnott appears 

 the most so ; but both, in com.mon w-ith all others that have yet been 

 promulgated, are incoirect both as to theory and fact. 



While our ideas of the structure of the most essential organ of the 

 plant, with reference to natural affinities, are thus vague, can it be 

 matter of surprise lhat we are unable to trace its relations, and determine 

 its affinities in the system of plants ? 



What then is a peponida ? I have said above that it is neither a one- 

 celled fruit with parietal placentas, nor a three-celled one with introflex- 

 ed central placentas. But before I can say what it is, and point out the 

 difference between it and a fruit of the usual construction, it is necessary 

 to state what the usual structure is. This I shall do by means of a short 

 extract from Lindley's Key to Structural Botany, 



354. " A Carpel is formed by a folded leaf, the upper surface of 

 •which is turned inwards, the lower outwards ; and the margins of which 

 develope one or a greater number of buds, which are the ovules. 



355. When the carpels are stalked, they are said to be seated upon 

 a thecaphore, or gynopJiore ; Ex. Cleome, Passiflora. Their stalk is 

 analogous to the petiole of a leaf. 



