STRUCTURE OF FRUIT. 143 



legume contain several seeds, the dehiscence takes place 

 in one of the two following ways : — when the fruit is uni- 

 locular, each of the valves splits lengthways along the 

 middle, forming two longitudinal ruptures ; this takes 

 place in the legume of Hcematoxylon : or when the 

 fruit is divided into transverse cells, as I have above 

 explained, a rupture is made transversely along the 

 partition or contraction which separates the cells, and 

 each of them (which then take the name of Joints) 

 is found separated from the others, and transformed, as 

 it w r ere, into a pseudo-spermous fruit, which does not 

 open, but is sown with the seed enclosed. And here also 

 are presented two cases : sometimes, as in the He- 

 dysareae, each joint carries with it the two sutures 

 perfectly entire; sometimes, as in several Mimoseae, the 

 sutures remain, and the cells open at the same time that 

 they separate from one another. 



In all these cases, it evidently results from the 

 dehiscence that the seeds, when they are numerous in 

 the same carpel, are permitted to be dispersed so as to 

 be sown separately. 



We have already said that the seeds are attached 

 either to the inner margin of the carpellary leaf, and, 

 consequently, along the ventral suture, or at the base or 

 apex of the carpel, but always laterally, and in reality 

 near the top or bottom of the ventral suture. These 

 three positions, then, differ only in this, that in the first 

 case they arise all along the suture, in the second only 

 at its base, in the third only at the apex. In every case, 

 the portion of the carpellary leaf from which the seeds 

 arise, has received the name of Placenta. 



The placenta is usually a kind of thick ridge, com- 

 posed of spongy cellular tissue, and pierced by two sets 

 of fibres : the first, which proceeds from the peduncle, 

 conducts the nourishing fluids ; the other, which comes 



