CHAPTER XIII. 

 INFLORESCENCE 



INFLORESCENCE is the arrangement of flowers. There are 

 two types of inflorescence, indeterminate and determinate. 

 In all forms of indeterminate inflorescence the lowest flower 

 opens first; therefore, flowers may continue to develop as 

 the stem elongates. In all forms of determinate inflorescence 

 the first flower to open is located at the tip of the already 

 mature stem. Such an inflorescence can have only as many 

 additional flowers as there are buds at the time the terminal 

 flower opens. 



Parts of an Inflorescence. The parts of the typical inflores- 

 cence are as follows : a peduncle or modified stem which bears 

 the flowers; pedicle or the stem of the individual flower; a 

 bract or modified leaf, in the axil of which the pedicle occurs; 

 and a flower which bears the organs of reproduction. 



It should be noted that the peduncle, a modified stem, is 

 made up of nodes and internodes and that in some forms the 

 internodes are so far apart that the flowers are separated, 

 as in the raceme of digitalis. The peduncle of the spadix of 

 sweet flag is elongated but the internodes have not developed ; 

 the nodes and therefore the flowers are close together. In 

 the head of buttonbush the peduncle is spherical and all 

 traces of the internodes have disappeared. In the umbel of 

 milkweed the internodes are undeveloped but the flowers are 

 separated, because each flower has a long pedicle. Other 

 variations will be noted in studying the types of inflorescence. 



