AMERICAN WILD FLOWERS 



459 



variously estimated at from fifteen to twenty thousand. The 

 Thistle Family (Carduaceae) is the largest family in the group, with 

 some ten thousand widely distributed species. 



For convenience, members of this family may be separated 

 into two groups depending upon the types of flowers found in the 

 head. Disc flowers only are found among the ironweed, boneset, 

 pearly everlasting, burdock, thistle and basket flower genera 

 (fig. 279). Ray and disc flowers both occur in the asters, golden- 

 rods, sunflowers, black-eyed Susan, desert gold, firewheel, yar- 

 row, white daisy and sagebrush (fig. 280). 



Fig. 279. — Members of the Thistle Family with disc flowers only in the flower 

 head include ironweed (A) and boneset (B). 



Ironweed, of the eastern and southern states, is a tall plant 

 with narrow leaves and heads made up of thirty or more small 

 purple flowers. Boneset is also a stout stemmed plant, inhabiting 

 wet meadows of eastern United States; each flower head consists 

 of a dozen or more grayish white flowers. Joe-pye w^eed, a related 

 species with purplish flowers, grows in moist places from New 

 England to Texas. Pearly everlasting is a familiar silvery white 

 flower found in sunny fields throughout the United States; the 

 central mass of white tubular flowers is surrounded by many 

 pearly white bracts. Pussy toes is a somewhat similar genus with 



