PLANT ORGANS AND ORGANISMS 



177 



INFLORESCENCE 



Inflorescence or Anthotaxy. A typical flower consists of four 

 whorls of leaves modified for the purpose of reproduction, and com- 

 pactly placed on a stem. The terms Inflorescence and Anthotaxy 

 are applied to the arrangement of the flowers and their position on 

 the stem, both of which are governed by the same law which deter- 

 mines the arrangement of leaves. For this reason flower buds are 

 always either terminal or axillary. In either case the bud may de- 

 velop a solitary flower or a compound inflorescence consisting of 

 several flowers. 





p 



p 

 p 

 p 



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7 



B 



FIG. 90. Types of indeterminate inflorescence. A, A raceme; B, a spike; C, a 

 catkin; D, a corymb; E, an umbel. The flowers are represented by circles; the 

 age of the flower is indicated by the size. (From Hamaker.) 



Determinate, cymose, descending, or centrifugal inflorescence is that 

 form in which the flower bud is terminal, and thus determines or 

 completes the growth of the stem. Example: Ricinus communis. 



Indeterminate, ascending, or centripetal inflorescence is that form in 

 which the flower buds are axillary, while the terminal bud continues 

 to develop and increase the growth of the stem indefinitely. Exam- 

 ple: the Geranium. 



Mixed inflorescence is a combination of the other two forms. 

 Example: Horse Chestnut. 



