MARYLAND WEATHER SERVICE 4S9 



Nabalus serpentarius (Pursh.) Hook. Lion's-foot. 



Cecil County, Conowingo (407). 



Nabalus trifoliatus Cass. Tall Rattlesnake-root. 



Baltimore County, Warren (Robert K. Miller). 



AMBROSIACEAE. 



Iva frutescens L. Marsh Elder. 



Coastal Zone; along the margins of salt and brackish marshes, and 

 along the banks of estuaries; common. 



Ambrosia trifida L. Great Ragweed. 



Throughout the state; in moist waste situations; common. 



Ambrosia trifida var. integrifolia (Muhl.) Torr. & Gray. 

 Throughout the state; in waste situations; frequent. 



Ambrosia artemisiaefolia L. Ragweed. 



Throughout the state; in cultivated and waste grounds; one of the most 

 common weeds. 



Xanthium spinosum L. Spiny Clotbur. 



Throughout the state; in waste situations; infrequent. Introduced from 



Europe. 

 Cecil County, Charlestown (39S). 



Xanthium glabratum (DC.) Britton. Smooth Clotbur. 



Baltimore (W. Ralph Jones). 



Xanthium canadense Mill. Cocklebur. 



Throughout the state; in dry waste grounds; common. 



COMPOSITAE. 



Vernonia noveboracensis (L.) Willd. Iron Weed. 



Throughout the state; in marshes, swamps, open wet situations and 

 cultivated grounds; common. 



Elephantopus carolinianus Willd. Carolina Elephant's-foot. 



Common in the Coastal Zone, rare in the Midland Zone; in dry forests. 



Elephantopus nudatus A. Gray. Smoothish Elephant's-foot. 



Coastal Zone; in dry forests of the southern Eastern Shore; frequent. 

 Worcester County, Snow Hill (1049). 



Sclerolepis uniflora (Walt.) Porter. 



Coastal Zone; sandy lake margins; rare. 

 Wicomico County, Humphrey Pond (1346). 



Eupatorium purpureum L. Joe-pye Weed. 



Throughout the state; in moist open situations; common. 



Eupatorium verbenaefolium Michx. 

 Coastal and Midland Zones. 



