194 



ELEMENTS OE BOTANY. 



thickened adherent calyx makes up a peculiar fruit (with a 



firm outer rind) known as the pepo. The relative bulk 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 ? 



234. 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 fruit, but it 

 does in the last two, and 

 in a great number of 

 berries. 



The gourd-fruit and the 

 hesperidiuTn, such as the 

 orange, Tig. 181, lemon, 

 and lime, are merely de- 

 cided modifications of the 

 berry proper. 



235. Aggregate Fruits. 

 — The raspberry, black- 



Fic. 181. — Cross-Sectiou of au Orange. 

 [t, axis of fruit with dots showing cut-off 

 ends of fibro-vascular bundles ; p^ partition 

 between cells of ovary ; S, seed ; c, cell of 

 ovary, tilled witli a pulp composed of irregu- 

 lar tubes, full of juice ; o, oil reservoirs 

 near outer surface of rind ; e, corky layer of 

 epidermis. 



berry, Fig. 182, 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 ? 



