AEBANGEMENT OF FLOWERS OK THE STEM. 



133 



called a head (Fig. 109). Arodnd the base of the head usually 

 occurs a circle of bracts known as the involucre, well shown 

 in Fig. 110. The same name is given to a set of bracts which 

 often surround the bases of the pedicels in an umbel. 



167. The Anthodlum. — The plants of one large group, of 

 which the dandelion, the daisy, the thistle, and the sunflower 



I n 



Fig. 108. — Catkins ofWillow. 

 I, Staminate flowers ; II, Pistillate flowers. 



Fig. 107.— 

 Spike of 

 Plantain. 



Fig. 109. — Head of Eryngo. 



are well-known members, bear their flowers in close involu- 

 crate heads on a common receptacle. The whole cluster 

 looks so much like a single flower that it is usually taken for 

 one by non-botanical people. This kind. of head has received 

 the special name of anthodium. In many of the largest and 



