REPRODUCTION BY SEED 



181 



The head (Fig. 80) is the characteristic inflorescence of 

 the Dandelion family, the scabious, thrift, etc. The 

 flowers are small, very closely packed, and surrounded 

 by a ring of small leaves (bracts). 



FIG. 79. DIAGRAM OF CYME. 



The umbel (Fig. 81) occurs in the Parsley family (the 

 Umbelliferae), the onion, narcissus, pelargonium, etc. The 

 flowers are again usually closely packed, and in some of 

 the Umbelliferse e.g., hogweed the outermost petals of 



FIG. 80. DIAGRAM OF HEAD (CAPITTJLUM). 



each flower are enlarged to increase the size and con- 

 spicuousness of the whole cluster. 



In considering the biological significance of the various 

 forms of inflorescences, we see that in all cases the flowers 

 are so arranged as to increase the chances of pollination. 



