222 APPLIED BIOLOGY 



mer and becomes the " hull " or " shuck." Before this 

 hardening occurs, young English walnuts are sometimes used 

 for making pickles. Obviously, a hulled walnut or hickory- 

 nut corresponds in origin to a peach or plum stone. 



(L) Examine any stone-fruits available. Also flowers and 

 young stages preserved in formalin. 



Aggregates of Stone-fruits. Raspberry and blackberry. 

 Each of the small rounded bodies of which these berries 

 are composed is a stone-fruit, developed from an ovary. The 

 whole berry is an aggregate of fleshy fruits ; and each one of 

 these bodies corresponds to a cherry. The numerous pistils of 

 the flowers are crowded so closely together that the resulting 

 fruits become united into the one mass which we know as 

 a blackberry or raspberry. This mass when ripe separates 

 easily from the receptacle. In short, a blackberry or rasp- 

 berry is equivalent to many small cherries which we might 

 imagine growing together into one solid mass set on one large 

 receptacle. Blackberry flowers and green berries preserved 

 in formalin should be examined. 



216. Complex Fleshy Fruits are formed from an ovary 

 plus some adjoining flower parts. All the fruits described 

 in the preceding sections are formed from the ovary only. 

 In some complex cases the receptacle grows up around the 

 ovary as in Fig. 63, C; the ovary therefore appears to be 

 below the calyx and corolla (inferior ovary), and the fruit 

 formed is composed of ovary and thickened receptacle (apple 

 and cucumber). 



Apple. (L) Materials : Apples, apple flowers, and various stages 

 of the young fruit in formalin. Optional, pears and quinces. 



Note the dried-up ends of sepals at end opposite the stem. Com- 

 pare series of stages from flower to the young fruit. Observe the 

 waxy coating on the skin. Suggest use. Remove the skin from an 

 apple, put aside the peeled apple and examine it after a day or two. 

 Use of the skin? 



Cut the apple crosswise midway between the stem and sepal 

 ends. Note the star-like arrangement of the seed-cavities. How 



