112 COLLEGE BOTANY 



usually spoken of incorrectly as seeds, but since they are endoaed 

 in the ovary they must be classed as true fruits (see page 120). 

 {d) The nut is a fruit with a single seed in which the ovary 

 is usually developed into a hard, bony or horny covering. There 

 are three distinct types of nuts, as follows: the acorn type 

 (Fig. 80, d), in which the fruit is borne in a cup composed of 

 involucral leaves; the hazelnut, chestnut and beechnut type, in 

 which the involucral leaves grow around and completely enclose 

 the nuts; and the 'hickory and walnut type, in which we are 

 somewhat uncertain as to the origin of the outside structure; 



Fig. 81. — Types of dehiscent fruits; (a) pod or capsule, (b) follicle, (c) legume, 

 (d) silique, (e) pyxis. 



the shuck or hull probably consists partly of calyx and partly 

 of involucral leaves. 



The most important of the dehiscent fruits (Fig. 81 ) are : 



(a) The capsule, which is a dry, matured ovary, consisting 

 of two or more carpels (i.e., a compound pistil) (Fig. 81, a). 

 The capsules open in various ways. 



(h) The follicle is a capsule derived from a single carpel 

 (i.e., simple ovary) and opening along the ventral or upper 

 suture, as in the case of the larkspur and poony, or the dorsal 

 suture, as in magnolia (Fig. 81, b). 



(c) The legume is the Avj pod or fruit derived from a single 

 carpel and opening along both sutures, as in the bean and pea 



