THE PISTIL. 



139 



receptacle. The cases of the Rose, Cherry, and Apple 

 have already been referred to (Chapter VI. ). 



217. In our examination of the Marsh Marigold (Figs. 

 24 and 25) we found an apocarpous pistil of several 

 carpels. We found also that each carpel contained a 

 number of seeds, and that in every case the seeds were 

 attached to that edge of the carpel which was turned 

 towards the centre of tlie flower, and that, as the carpels 

 ripened, they invariably split open along that edge, but 

 not along the other, so that the carpel when opened out 

 presented the appearance of a leaf with seeds attached to 

 the margins. The inner edge of a simple carpel, to 

 which the seeds are thus attached, is called the ventral 

 suture, the opposite edge, corresponding to the mid-rib 

 of a leaf, being the dorsal suture. 



218. If we suppose a number of simple carpels to 

 approach each other and unite in the centre of a flower, 

 it is evident that the pistil so formed would contain as 

 many cells as there were carpels, the cells being separated 

 from each other by a double wall, and that the seeds 

 would be found arranged about the centre or axis of the 

 pistil ; and this is the actual state of things in the Tulip, 

 whose pistil is formed by the union of three carpels. 

 When the pistil ripens, the double walls separating the 

 cells split asunder. To these separating walls the name 

 dissepiment or partition is given. 



219. The cells are technically known as loculi. An 

 ovary with one cell is unilocular ; with two, bilocular ; 

 with several," multilocvlar. Between the unilocular and 

 multilocular forms there are all shades of gradation. In 

 some cases, as, for example, in Saxifrage, the carpels 



