246 
IOWA ACADEMY OF SCIENCES. 
Hieracium L. Hawk-weed. 
518. H. canadense Michx. Woods west of Estherville;; 
infrequent. 
Nab alus Cass. 
519. N. albus (L.) Hook. ( Frenanthes alba L.) Rare;. 
woods along west fork of Des Moines. 
520. N. asper (Michx.) Torr. and Gray. ( Frenanthes 
aspera Michx.) Frequent on prairies. 
521. N. racemosus (Michx.) D C. Frenanthes racemosa 
Michx. Frequent on prairies. 
AMBROSIACE^E. 
Iya L. 
522. I . xanthiifolia (Fresen.) Nutt. A troublesome 
weed in rich ground; introduced from the 
Northwest about 1870. 
Ambrosia L. 
523. A. trifida L. Great Ragweed. Very common; 
woods and waste places. 
524. A. artemisicefolia L. Common Ragweed. A very 
common and troublesome weed. 
Xanthium L. 
525. X. canadense Mill. Cockle-bur. Common along 
streams and introduced into cultivated fields. 
CARDUACE^:. 
Vernonia Schreb. 
526. V. fasciculata Michx. Iron-weed. Common in 
low ground. 
Eupatorium L. 
527. E. purpureum L. Trumpet-weed. Frequent in 
woods along west fork of Des Moines. 
528. E. ageratoides L. f. White Snakeroot. Very 
common in woods. 
529. E. perfoliatum L. Boneset. Common; low places, 
woods and prairies. 
Kuhnia L. 
530. K. eupatorioides L. Dry knolls and river banks; 
common. 
