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 ovary and its 



contents. In the first three 



cases above mentioned the 



calyx forms no part of the ^S^SQi 



fruit, but it does in the last 



two, and in a great number 



of berries. 



The gourd-fruit and the 

 .hesperidium, 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 ? 



FIG. 171. Cross-Section of an Orangr. 

 a, axis of fruit with, dots showing cut-off 

 ends of nbro-vascular 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 ; e, corky layer of epidermis. 



