136 



INFLORESCENCE 



166. Compound flower clusters. If the pedicels of a raceme 

 branch, they may produce a compound raceme, or panicle, like 

 that of the oat (Fig. 145). 1 Other forms of compound racemes 

 have received other names. 



An umbel may become compound by the branching of its 

 flower stalks (Fig. 146), each of which then bears a little umbel, 

 called an iimbellet. 



167. Inflorescence diagrams. The plan of inflorescence may 

 readily be indicated by diagrams like those of Fig. 147. 



p 

 P 

 f 



f 



I 



/ 



A BCD 



FIG. 147. Diagrams of inflorescence 

 A, panicle; B, raceme; C, spike; D, head; E, umbel 



168. Terminal flowers ; determinate inflorescence. The ter- 

 minal bud of a stem may be a flower bud. In this case the 

 direct growth of the stem is stopped or determined by the 

 appearance of the flower ; hence such plants are said to have a 

 determinate inflorescence. The simplest possible case of this 

 kind is that in which the stem bears but one flower at its 

 summit. 



169. The cyme. Very often flowers appear from lateral 

 (axillary) buds, below the terminal flower, and thus give rise to 

 a flower cluster called a cyme. This may have only three flowers, 

 and in that case would look very much like a three-flowered 



1 Panicles may also be formed by compound cymes (see Sec. 169). 



