INFLORESCENCE. 69 



Inflorescence. 



112. The manner in which flowers are arranged on the 

 flower-bearing stem, or branch, is termed Inflorescence, or An- 

 thotaxis (antkos, a flower, and taxis, order). From the fact 

 that all floral organs are modifications of leaves, and have the 

 same origin, it follows, of course, that primarily they have the 

 same arrangement, however modified this arrangement may 

 become in the course of development. The small branch which 

 bears a single flower or bunch of flowers is called the peduncle. 

 When the peduncle bears many flowers, the little organ that 

 supports each flower is called a pedicel. Sometimes the pe- 

 duncle is itself divided, and its divisions are called branches. 



When the peduncle rises from the earth and bears the flower, 

 it is called a scape. A rachis is a peduncle that proceeds 

 through the center of the inflorescence from the base to the 

 apex. It is also called the axis. 



When the part that bears the flower, instead of being 

 lengthened into a rachis, forms an enlarged and flattened sur- 

 face at its extremity, on which the flowers are arranged, it is 

 called a receptacle. 



113. We may easily reduce all the various forms of inflo- 

 rescence to two primitive types, the determinate and indeter- 

 minate arrangements. 



By determinate arrangement is meant that kind of inflores- 

 cence which occurs when the primary axis of the plant is ter- 

 minated by a flower (meaning by the primary axis the stem 

 arising from the root). 



The most simple case of this kind is when the stem bears a 

 single flower, there being no secondary axes. 



114. The following are the most common Fig - 107> 

 forms of determinate inflorescence : 



Corymb is when the flower-bearing branch- 

 es arise from different points of elevation on 

 the stem, but rise to the same height. (Fig. 

 107.) It is simple when each secondary axis 

 bears a single flower, and compound when 

 their axes are divided and each division bears 



n Corymb. 



a flower. 



Capitulum or Head is produced when the flowers stand 



112. What is an inflorescence ? What is a peduncle ? Pedicel ? What 

 is a scape? Rachis? What is a receptacle? — 113. What is meant by 

 determinate inflorsscence ?— 114. What is a corymb? When simple! 

 When compound 1 What i» % capitulum I 



