222 THE FLOWER 



NATURE AND OFFICE OF THE FLOWER 



MATERIAL. Any kind of large flower may be used ; those of the 

 hollyhock, okra, cotton, hibiscus, or others of the mallow family are 

 recommended, as their pollen grains are large enough to be observed 

 fairly well with a hand lens. The cultivated Syrian hibiscus is the one 

 used in the text. 



319. Flower and Leaf. We have seen that the vena- 

 tion of petals and sepals corresponds in a general way 

 with that of foliage leaves of the class to which they be- 

 long, and that their arrangement around their axis is analo- 

 gous to the arrangement of foliage leaves on the branch. 

 We learned also, in our study of inflorescence, that flowers 

 and flower buds occur only in the same positions where 

 leaf buds occur, and that they are subject to the same laws 

 of arrangement and growth. 



320. Transformation of Organs. In our study of fruits 

 we saw that the carpels of the ovary are merely trans- 

 formed leaves. We learned, also, in our study of leaves, 

 something about the wonderful transformations that these 

 organs are capable of undergoing ; and lastly, we have 

 found some of these transformations taking place under 

 our eyes in the leaflike sepals and petal-like filaments 

 of the star-of-Bethlehem, in the bracts of the cactus, 

 the scales of winter buds, and numerous other instances 

 recorded in the preceding pages. 



It must not be supposed, however, that an organ is ever 

 developed as one thing and then deliberately changed into 

 something else. When we speak loosely of one organ 

 being transformed into another, the meaning is merely that 

 it has developed into one thing instead of into something 

 else that it was equally capable of developing into. 



321. The Flower a Transformed Branch. For the rea- 

 sons mentioned, the flower is regarded by botanists as 

 merely a branch with transformed leaves and the inter- 

 nodes indefinitely shortened so as to bring the successive 

 cycles into close contact, the whole being greatly altered 

 and specialized to serve a particular purpose. 



