THE FRUIT 189 
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 hesperidiwm, such as the orange 
(Fig. 141), lemon, and lime, are merely decided modifica- 
tions of the berry proper. 
231. Aggregate Fruits.—The raspberry (Fig. 142), 
blackberry, 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. 
What is the most important difference in structure 
between a fully ripened raspberry and a blackberry ? 
232. Accessory Fruits and Multiple Fruits. — Not infre- 
quently, as in the strawberry (Fig. 142), the main bulk of 
the so-called fruit consists neither of the ripened ovary 
nor its appendages. Such a combination is called an 
accessory frutt. 
Examine with a magnifying glass the surface of a small unripe 
strawberry, then that of a ripe one, and finally a section of a ripe 
