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BOTANY 



The essential parts of the flowers are, of course, the sporophylls, 

 stamens and carpels, which, in the lower floral types, are in separate 

 flowers, often upon different plants. Such flowers are " Diclinous." 

 In the more specialized flowers, stamens and carpels are usually 

 together, and the flowers are " Perfect " or " Hermaphrodite." In the 

 typical angiospermous flower, the sporophylls are surrounded by a 

 series of sterile leaves, the floral envelope, or Perianth. These leaves 



FIG. 314. Nymphsea tvberosa, showing gradation of floral leaves. (After BAH.EY.) 



are in part protective, but they may also be conspicuously colored, 

 and so render the flowers attractive to insect visitors. 



The typical angiospermous flower consists of a series of floral 

 leaves, arranged either spirally or in whorls about the apex of the 

 shoot, or floral axis. Where this axis is expanded it is termed a 

 Receptacle. The outermost leaves, the Sepals, are usually green, 

 and are mainly protective in function. These together constitute 

 the Calyx. The second series, the Petals, are generally larger and 



