ON FRUITS AND SEEDS. 



363 



I have already alluded to our cardamines, the pods of which open 

 elastically and throw their seed some distance. A Brazilian species, 

 C. chenopodifoUa (Fig. IT), besides the usual long pods (Fig. 17, a a), 

 produces also short, pointed ones (Fig. 17, ^ b), which it buries in the 

 ground. 



Arachis hypogcpxi is the ground-nut of the AYest Indies. The 

 flower is yellow and resembles that of a pea, but has an elongated 

 calyx, at the base of which, close to the stem, is the ovary. After the 

 flower has faded, the young j^od, which is oval, pointed, and very 

 minute, is carried forward by the growth of the stalk, which becomes 

 two or three inches long and curves downward, so as generally to force 

 the pod into the ground. If it fails in this, the pod does not develop, 

 but soon perishes ; on the other hand, as soon as it is underground, 

 the pod begins to grow and develops two large seeds. 



In Yicia ampliicarpa (Fig. 18), a south European species of vetch. 



Fig. 19. Lathtrus amphicarpos. (After Sowerby.) a, ordinary pods ; h, subterranean pods. 



there are two kinds of pods. One of the ordinary form and habit (a), 

 the other (^) oval, pale, containing only two seeds, borne on under- 

 ground stems, and produced by flowers which have no corolla. 



