243 UNIVERSITY OF MISSOURI STUDIES [3^4- 



1050. L. Canadensis L. Common wild lettuce. 

 Common in waste places and thickets. 



Nova Scotia to Saskatchewan; Florida to Louisiana and 

 Colorado. 



1051. L. sagittifolia Ell. [^L. iniegri/olia BigeL']. Entire- 

 leaved WILD lettuce. 



Common in waste places, wild fields and thickets. 

 New Brunswick to Ontario and Idaho; Georgia to Mis- 

 souri and Kansas. 



1051a. L. sagittifolia Ell. x L. Canadensis L. 



University Avenue, Columbia. 



1052. L. Ludoviciana (Nutt.) DC. Western lettuce. 

 Frequent along roadsides. 



Minnesota to North Dakota; Arkansas to Texas. 



433. CREPIS L. Hawksbeard. 



1053. C. setosa Hall. Hairy hawksbeard. 



A common weed in an alfalfa field in a flat along Grind- 

 stone creek. 



Europe, thence to Missouri. This seems to be the first 

 occurrence of the plant in the United States. 



434. PRENANTHES L. [NABALUS Cass.]. 

 Rattlesnake-root. 



1054. P. crepidinea Michx. \N . crepidineiis (Michx.) DC.]. 

 Large rattlesnake-root. 



Rare in thickets about Brushwood lake. 

 Pennsylvania to Minnesota; Tennessee to Kansas. 



1055. P. altissima L. \N. altissimus (L.) Hook.]. Tall 

 rattlesnake-root. 



Frequent in woods and thickets. The plants have bright 

 brown pappus which seems to be peculiar to Missouri forms. 



Newfoundland to Manitoba; Georgia to Tennessee 

 and Missouri. 



