Parthenium 



COMPOSITAE 



959 



50 



Map 2098 



Silphium integrifolium Michx 



Silphium integnfolium 



— 1o 



Map 2100 



Parthenium integnfolium L 



5a. Silphium integrifolium var. Deamii Perry. (Rhodora 39 : 287. 1937.) 

 Map 2099. Found throughout the range of the species but rarely found 

 closely associated with it in Indiana. 



Ind. and Wis., southw. to Ala., Miss., and Ark. 



9138. PARTHENIUM L. 



1. Parthenium integrifolium L. American Feverfew. Map 2100. 

 This is one of our typical prairie plants. Since all of our original prairies 

 are under cultivation, this plant is found now only in prairie habitats along 

 roadsides and railroads. I have a few specimens collected in "oak open- 

 ings," which means that the plants are relicts. The range in Indiana is 

 extended by published records from Clark, Floyd, Jefferson, and Marshall 

 Counties. 



Md. to Minn., southw. to Ga. and Ark. 



9141. IVA L. 



Heads subtended by leafy bracts; fertile flowers with evident corollas 1. I. ciliata. 



Heads not subtended by leafy bracts; corollas of fertile flowers rudimentary or lacking. 

 2. /. xanthifolia. 



1. Iva ciliata Willd. Map 2101. Known only from Gibson and Posey 

 Counties. I found it to be frequent to common in hard, clay soil in a field 

 on the border of Pitcher's "Lake," along the roadside on the south side of 

 Half Moon Pond, and along the roadside for a mile or more along the 

 Wabash River in the vicinity of Bone Bank, Posey County. 



Ind. to Nebr., southw. to La. and N. Mex. 



2. Iva xanthifolia Nutt. Reported by Hansen as found along a ditch 

 in Tippecanoe County, and by Peattie as found in the Calumet District. 

 Although I have not seen a specimen, I am admitting this species because 

 there is little possibility of a wrong determination. 



Ont. and Mich, to Sask., southw. to Tex. and Utah; introduced in the 

 East, from Maine to Del. 



