IOWA ACADEMY OP SCIENCES. 
235 
Taraxacum. 
600. T. taraxacum (L.) Karst. {T. officinale Weber.) 
Abundant everywhere . 
601. T. erythros]permum Andrz. With the preceding. 
SONCHUS. 
602. S. oleraceus L. Frequent in waste ground. 
603. S. asper (L.) All. With the preceding, but more 
common. 
Laotuca. 
604. L. scariola L. Nearly everywhere in cultivated 
and waste ground. 
605. L. canadensis L. Thickets and fields; common. 
606. L. Mrsuta Muhl. Fields and waste ground; com- 
mon. 
Hieracium. 
607. H. canadense Michx. Dry banks and woods or 
along streams; common. 
Nabalus. 
608. N. albus (L.) Hook. ,{Prenanthes alba L.) Woods 
and thickets; common. 
609. W. asper (Michx.) T. and G. (P. aspe7'a Michx.) 
meadows; frequent. 
610. N. racemosus (Michx.) DC. (P. racemosa Michx.) 
Moist ground in meadows and along railroads; 
infrequent. Our specimens are very large, 
eight or nine feet high, with the upper stem, 
pedicels and bracts shaggy, hirsute, and the lower 
leaves sessile or nearly so and deeply pinnatifid. 
AMBROSIACE^. 
Ambrosia. 
611. A. trifida L. Moist fields and roadsides; too 
abundant. 
612. A. artemisicefolia L. Fields and waste ground; 
abundant. 
613. A. psilostachya D C. With the preceding, but 
scarce. 
