138 VEGETABLE ORGANOGRAPHY. 



3d. Folded upon their middle nerve, so that the 

 margins are applied to each other, forming a longitu- 

 dinal line, as in the Pea, Bean, &c. 



4th. As the leaves are curved or folded, their two 

 seminiferous margins may be more or less folded in- 

 wards, so as to divide the carpel by semi-partitions, or 

 by longitudinal ones, as in Astragalus. 



5th. The dorsal nerve of the carpel or the middle one 

 of the leaf, may be so pushed inwards, as to form a pro- 

 jection which also tends to divide the carpel into two 

 longitudinal cells, as in Oxytropis. 



These different modes of folding or curving of the leaf, 

 correspond, as it is easy to ascertain, with the modes 

 already described, of the rolling or folding of the leaves 

 in the bud. When the carpels are formed of a leaf, 

 folded lengthways upon itself, the two lateral surfaces 

 may be either flat, as in Spartium Junceum, or more or 

 less convex, as in the Bean, or Crotolaria, or folded at a 

 more or less obtuse angle, a combination which in 

 general takes place only by the pressure of neighbour- 

 ing organs. 



The line formed by the approximation of the two 

 margins of the leaf, and which represents a suture, is 

 called the Seminiferous Suture, because it is upon its 

 inner edge that the seeds are usually attached, or the 

 Ventral Suture, because it is opposite the back of 

 the carpel. 



When the carpel is formed of a leaf curved longitudi- 

 nally, it only presents this suture, and receives then the 

 particular name of Follicle, (folliculus.) It is called 

 a Cocca when the suture opens with elasticity. 



When the carpel is formed by a leaf folded upon its 

 middle nerve, it frequently happens that, at maturity, 

 the dehiscence takes place along this nerve, which 

 has for this reason received the name of the Dorsal 



