96 . IOWA ACADEMY OF SCIENCE 
PARTHENIUM L. 
923. Parthenium integrifolium L. American Fever-Few. Scarce and 
local; Riverside and Elmira. 
IVA L. 
924. Iva xanthifolia Nutt. Bur-weed Marsh Elder. A common weed, 
especially along streams. 
AMBROSIA (Tourn) L. 
925. Ambrosia trifida L. Bitter-weed or King Head. A common weed 
of waste places, 
926. Ambrosia trifida Var. integrifolia (Muhl.) T. & G. With the 
above but less common. 
927. Ambrosia artemisiifolia L. Ragweed. An abundant weed of fields 
and roadsides. 
928. Ambrosia psilostaSua DC. Western Ragweed. Also abundant 
but more common in dry soils. 
XANTHIUM (Tourn) L. 
929. Xantliium canadense Mill. American Cocklebur. A common weed 
in waste places and along streams. 
HELIOPSIS Pers. 
930. Heliopsis scabra Dunal. Rough Ox-eye. A common weed of 
fields and roadsides. 
ECLIPTA L. 
931. Eclipta alba (L.) Hassk. Mud Daisy. Common along streams; 
introduced put persisent. 
RUDBECKIA L. 
932. Rudbechia triloba L. Thin-leaved Cone Flower. Very common 
in moist wooded places. 
933. Rudbechia subtomentosa Pursh. Sweet Cone Flower. Common 
in moist fields and meadows. 
934. Rudbechia hirta L. Black Eyed Susan. Very abundant in fields, 
roadsides and meadows. 
935. Rudbechia laciniata L. Tall or Green Headed Cone Flower. Com- 
mon in moist wooded places. 
