THE FRUIT 



225 



of enlarged calyx and of ovary in such fruits is not always 

 the same. 



How does the amount of material derived from fleshy 

 and thickened placentae in the squash compare with that 

 in the watermelon ? 



245. The Berry. — The berry proper, such as the 

 tomato, grape, persimmon, gooseberry, currant, and so on, 

 consists of a rather thin- 

 skinned, one- to several- 

 celled, fleshy ov^ry and its 

 contents. In the first three 

 cases above mentioned the 

 calyx forms no part of the 

 fruit, but it does in the last 

 two, and in a great number 

 of berries. 



The gourd-fruit and the 

 hegperidium, such as the 

 orange (Fig. 171), lemon, 

 and lime, are merely de- 

 cided modifications of the 

 berry proper. 



246. Aggregate Fruits The raspberry, blackberry 



(Fig. 172), and similar fruits consist of many carpels, each 

 of which ripens into a part of a compound mass, which, 

 for a time at least, clings to the receptacle. The whole is 

 called an aggregate fruit. 



To which one of the preceding classes does each unit of 

 a blackberry or of a raspberry belong ? 



What is the most important difference in structure 

 between a fully ripened raspberry and a blackberry ? 



Pig. 171. — Cross-Section of an Orange. 

 a, axis of fruit witli dots showing cut-off 

 ends of fibro-Tascular bundles ; p, parti- 

 tion between cells of ovary ; S, seed ; 

 c, cell of ovary, filled with a pulp com- 

 posed of irregular tubes, full of juice ; 

 o, oil reservoirs near outer surface of 

 rind ; c, corky layer of epidermis. 



