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 placentz 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 
fruit, but it does in the last 
two, and in a great number 
of berties. 
The gourd-fruit and the 
hesperidium, such as the 
Fic. 171. — Cross-Section of an Orange. 
F a, axis of fruit with dots showing cut-off 
orange (Fig. 171), lemon, ends of fibro-vascular bundles ; p, parti- 
3 tion between cells of ovary; S, seed; 
and lime, are merely de- c, cellof ovary, filled with a pulp com- 
: : . posed of irregular tubes, full of juice; 
cided modifications of the o, Oil reservoirs near outer surface of 
rind; e, corky layer of epidermis. 
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 ? 
