236 



PLANT LIFE. 



leaves adjacent are modified in form and color to adapt them 

 to securing the dispersal of the jjollen by N'arious agents, 

 especially insects. Such a shoot bearing sporojjhylls and 

 accessory leaves is called ?^ flower ( •, 330). As a similar 

 aggregation of the sporo])hylls occurs in horsetails and many 

 club-mosses (figs. 235, 240), it is evident that tlie flower is 

 not distinctive of the seed plants, though it attains the highest 

 specialization among them.* 



The parts and functions of the flower of seed plants are 

 now to be discussed. 



The Flower. 



330. A flower, in its simplest form, may consist of an axis 

 bearing only a single sporoijhyll (fig. 243). A flower usually 

 consists of a shortened axis, the iurus, bearing several sporo- 

 phylls and several accessory floral leaves (figs. 104, 244J. 



in,. 243.— ,J, a single flower; /,', .i purlidii ol the flower cluster of Arisarinii :'i<!s:are. 



The flower is composed of one stamen only. Magnified slightlv.— After Engler." 

 Fig. 244.— a flower of linden, halved ; slujwing a pestle-like'pistil. Magnified about 3 



diani. — After Kerner. 



The sporophylls arc known as essenlial organs, the accessory 

 leaves as the pcruinlli and brads. 



The essential organs are of two sorts, slamcns and carpels. 

 In any flower the}- may be all staiuens or all iar]icls, or may 



* It is f(ir this reason that the tenii .nn/ plants is pi-elerred ^o Jiown-ing 

 plants. 



