FRUITS 



263 



Fig. 389. — Follicle 

 of milkweed. 



Fig. 390. — Leaf- 

 like follicle of Japan 

 varnish tree : S, 

 outer(dorsal) suture ; 

 S', inner (ventral) 

 suture. 



298. Dehiscent fruits. — Pod, or capsule, is the general 

 name applied to all dehiscent fruits. The simplest possible 

 kind of pod is the follicle, composed of a 



single carpel, like those of 

 the larkspur, milkweed, and 

 marsh marigold, and may be 

 regarded as a modified leaf. 

 Examine one of these pods 

 and you will find that it 

 splits down one side, which 

 corresponds to the edges of 

 the leaf brought together 

 and turned inward to form 

 a placenta for the attach- 

 ment of the seed. This line 

 of union is called a "su- 

 ture," from a Latin word 

 meaning a "seam." 



299. The legume. — Get a pod of any kind of bean or 

 pea, and observe that it differs 

 from the follicle in having two 

 sutures or lines of dehiscence. 

 One of these runs along the back 

 of the carpel and corresponds 

 to the midrib of the leaf; the 

 other, corresponding to the 

 united edges of the carpellary 

 leaf, always turns inward, 

 toward the axis of the flower, 

 and forms the placenta. 



The beggar-ticks, so unpleas- 

 antly familiar to most of us, 

 are merely a kind of legume con- 

 stricted between the seeds and 



breaking up into separate joints ff^^^^ ^^ ^ ^^^ ^ith partially con- 

 at maturity. What kind of 



391 



Figs. 391-393. 

 legume of bean : 

 d, dorsal suture ; 



392 393 



— Legumes: 391, 

 , ventral suture ; 

 392, constricted 



legume of senna (CassiaNelsonia); 393, 

 legume of a 

 Btricted pod. 



