[Chap. XXXII 



FLOWERS, FRUITS, AND SEEDS 



363 



carpels, or pericarp. The more complex fruits of flowering plants are 

 composed in part of enlarged carpels and in part of other structures 

 which develop from the receptacle, floral cup, or other parts adjacent to 

 the flower. The edible portion of an apple and the rind of a banana, for 

 example, develop from the floral cup and surround the ovulary. In the 

 flowers of many plants, such as apple, rose, banana, gooseberry, blue- 



FiG. 160. Types of fruits: A, legume (pea); B, drupe or stone fruit (peach); 

 C, berry (tomato); D, akene (buckwheat); E, pome (apple); F-G, several rip- 

 ened pistils on the receptacle of one flower, aggregate fruits (blackberry and 

 strawberry); H, several pistils enclosed in an enlarged urn-shaped floral cup 

 (rose); I, several pistils embedded in the enlarged apex of the floral axis (water 

 lotus); J, an enlarged stem tip with a central cavity containing many small flowers 

 (fig); K, a single flower of mulberry with thickened sepals and also the whole 

 flower cluster ripened as one compact fruit. J and K are types of multiple fruits. 



berry, cucumber, and sunflower, the floral cup partly or wholly encloses 

 the ovularies of the pistil and becomes a part of the fruit (Fig. 159). 

 The cups of acorns and the husks enclosing hickory nuts apparently 

 develop from involucral bracts that grow below the flower. We may 

 therefore consider a fruit as a plant organ that develops from one or 

 more carpels, together with any other closely associated flower part that 

 may enlarge and ripen with the carpels ( Fig. 160 ) . 



To many persons the term "fruit" refers only to certain edible struc- 

 tures, such as apples, pears, plums, and apricots, that grow on trees. 

 In certain practices the fruits of many herbaceous plants, such as tomato, 

 string bean, okra, pepper, cucumber, and squash, are popularly called 



