152 VEGETABLE ORGANOGRAPHY. 



when the retreating faces of the carpels are not inti- 

 mately united together ; or on the sides of the valves 

 when they are puffed up, as in Myogram ; or at the top 

 of the pedicel, or in the axis, when it is fistular ; or, 

 lastly, at the base of the style, when this base is, in like 

 manner, fistular. These last cavities are remarkable for 

 sometimes containing a seed, as is seen in Brassica 

 cheiranthos, and in Trianthema monogyna ; this kind of 

 seminiferous cavity or stylary cell is of rare occurrence, 

 and inexplicable by any carpological theory ; its detailed 

 observation merits the attention of anatomists. 



We have seen how the cells are formed in fruits by 

 the folding back of the margins of the carpels as far as 

 the axis; let us now examine what happens when the 

 retreating parts do not reach the centre. Three cases 

 are here presented to us : they either extend half-way in 

 from the top to the bottom, or they are so short as to 

 seem absent, or they nearly reach to the centre at the 

 base of the fruits, but are absent at the upper part. 



When the retreating parts of the carpels are prolonged 

 into the interior without reaching to the axis, there 

 results a fruit, the centre of which is empty and the 

 circumference presents as many cells, open on the inside, 

 as there are carpels ; these cells bear the name of Semi- 

 cells. The partitions, which are then called Semi- 

 partitions, bear the seeds on their inner margins, as 

 usual ; this is seen in certain Poppies and Hypericineae : 

 on comparing together the species of these two groups, 

 we meet with almost every degree, from partitions which 

 reach very nearly to the centre, to those which are so 

 short as hardly to have their edges visible. 



When the partitions are so short as to be hardly 

 visible, the placentse are then, as it were, applied to the 

 sides of the fruit, and each carpel is reduced to its 

 dorsal face. The fruit is then said to be Unilocular, 



