DAISY, DANDELION, AND THISTLE FAMILY 



407 



fail of insect pollination, they frequently curl back, until they 

 touch the pollen collected on the style itself, and thus effect 

 self-pollination. These stages may be readily followed in the 



Fig 137. Olearia insignis (i nat. size). 



dandelion, (cf. also Campanulaceae, p. 403). After pollina- 

 tion, the calyx tube usually grows upwards, bearing on its 

 summit a parachute of bristles or hairs (the pappus). In this 

 way the well known " clock " of the dandelion is formed. 

 The pappus hairs vary considerably in character, and generic 

 distinctions are sometimes based upon their differences. The 



