194 ELEMENTS OF 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 placentz 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 
hesperidium, such as the 
orange, Fig. 181, lemon, 
a, axis of fruit with dots showing cut-off and lime, are merely de- 
ends of fibro-vascular bundles; p, partition ejded modifications of the 
between cells of ovary; S, seed; c, cell of " 
ovary, filled with a pulp composed of irregu- erry proper. 
FiaG. 181. — Cross-Section of an Orange. 
lar tubes, full of juice; o, oil reservoirs 235. Aggregate Fruits. 
near outer surface of rind; e, corky layer of q b Llaeke 
epidermis. — The raspberry, black- 
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 ? 
