94 



PLANT BIOLOGY 



2. Many fleshy fruits are dispersed by birds and other 



animals which are seeking food. How are these 

 animals rewarded for doing this work? 



3. How are the seeds of ripe peaches and cherries, for 



example, protected from injury? 



105. Fruits and their classification. If one were asked 

 to give examples of fruits, one would doubtless give such 

 forms as apples, cherries, and peaches. But it is doubtful 

 if he would think of including among fruits, pea pods, pump- 

 kins, chestnuts, and corn. To 

 the botanist, however, these are 



FIG. 37. Lengthwise sec- 

 tion of apple fruit, showing 

 seeds attached to a central 

 placenta. (Bailey.) 



FIG. 38. Cross section of apple 

 fruit, showing seeds and their cov- 

 erings which constitute the core. 



considered to be just as truly fruits as the forms commonly 

 thought of as fruits. Let us see why such diverse plant 

 products as those just named are all included under the head- 

 ing of fruits. Technically, a fruit is a ripened ovary and its 

 contents with any other part of the plant that is closely incorpo- 

 rated with it; and since the forms named above are all ripened 

 ovaries containing one or more seeds, it is evident that, 

 strictly speaking, they must be classed with the fruits as 

 much as apples and cherries. 



Sometimes the flower contains a number of pistils which 

 form a pulpy mass,, such as the raspberries and blackberries 



