
HOW FRUITS ARE FORMED 175 
There are many other fruits which will be interesting 
to study. Some of these are treated of in the following 
chapter, since in many cases it is difficult to distinguish 
between a fruit and a seed. In the study of fruits you 
should see if you can tell of what use they are to 
the plant, and how these fruits may be the means of 
helping the plants to scatter their seeds. 
Note. —In the walnut, butternut, and hickory nut the fruit is 
different from that of the hazelnuts, oaks, etc. The “hull” or 
«“shuck ” probably consists partly of calyx and partly of involucral 
bracts consolidated, but very likely there is more of calyx than of 
involucre. The walnut and butternut are more often called drupes or 
stone fruits, but the fleshy part of the fruit is evidently not of the 
same origin as in the case of the true drupes, like the cherry, peach, 
plum, and others, 
