LESSONS IN BOTANY. 243 



the ovary, its margin, consisting of rigid or downy bristles, teeth 

 or scales is called the pappus. The end of the stalk on which the 

 simple flowers stand is the receptacle. The greater part of the 

 flower cluster is made np of tubular flowers, but often around 

 the margin of the cluster there are flowers whose corollas have 

 extended into a strap or leaf-like form called rays, which in many 

 cases seem to be the petals of ordinary flowers. Some well-known 

 members of this family are chickory, lettuce, dandelion, sun- 

 flower, golden-rod, chrysanthemum, thistle and burdock. 



