82 COMPOSITAE. 



eeolate, sparingly dentate or entire, rough-margined, acute or acuminate. 

 sessile or somewhat clasping, the lowest sometimes petioled; heads numer- 

 ous, rather large; involucre turbinate, its bracts linear-oblong, green-tipped, 

 acute or obtusish, appressed, in 4 or 5 series; rays many, violet, purplish, or 

 white. Low moist soil; common; Johnson, Henry, and Deeatur counties. 



A. paniculatus Lam. Stem 2-8 feet high, glabrous, paniculately 

 branched; leaves lanceolate or oblong-laneeolate, acuminate, base narrowed 

 and sessile or clasping, sparingly serrate to nearly entire; heads many, rather 

 b: - oad; involucre hemispheric, the bracts linear-lanceolate, acute or acumi- 

 nate, appressed, green-tipped, in 4 or 5 rows; rays many, white or purplish. 

 Moist soil; Fayette county, reported from Story, Woodbury, Lyon, Lee, and 

 Henry counties. 



A. tradescanti L, Stem 2-5 feet high, slender, paniculately branched, 

 branches ascending and sometimes pubescent iD lines; cauline leaves lanceo- 

 late cr linear-lanceolate, acuminate, narrowed to the sessile base, entire or 

 more commonly sharply serrate in the middle; heads numerous, racemose; in- 

 volucre hemispheric to broadly turbinate, its bracts linear, acute, green- 

 tipped, appressed. in 4 or 5 rows; rays white or whitish, short and narrow. 

 Fields and low places; specimens from Delaware and Johson county have 

 been referred to this species. 



A. ericoides L. Stem 1-3 feet high, bushy, paniculately branched, gla- 

 brous; leaves firm or rigid, the basal spatulate, obtuse, dentate, with mar- 

 gined-petioTes; cauline leaves linear, entire, acute, the uppermost linear-subu- 

 late; heads many; involucre hemispheric to cainpanu late, the bracts green- 

 tipped, linear-lanceolate or lanceolate, in about 3 rows; rays 15-25, white or 

 rosy tinged. Dry soil; Henry county, reported from Lee and Monona coun- 

 ties. 



i X $ \ Heads racemose and usually t-sldul an the branches. 



A. dif fusus Ait. Stem 1-4 feet high, much branched, pubescent or nearly 

 glabrous; leaves lanceolate or oblong-lanceolate, tapering both ways, sharply 

 serrate in the middle or the smaller entire, sessile, thinnish; heads disposed 

 singly or in clusters along the flowering branches; ra3'S short, white or some- 

 times purplish; involueral scales linear, obtuse or acutish. Low woods; com- 

 mon; Story, Fayette, Delaware, Johnson, Henry, Appanoose, and Decatur 

 counties. (A. lateriflora* (L.) liritton). 



A. multiflorus Ait. Stem about » foot high, busby-branchdd, grayish, 

 pubescent; leaves small, linear, entire, sessile or partly clasping; heads 

 small, crowded in numerous racemes; herbaceous tips of the involueral scales 

 spreading; rays white, rarely bluish. Sandy soil, woods and prairies: com- 

 mon; Winneshiek, Fayette, Floyd, Delaware, Scott, Muscatine, Des Moines, 

 Henry, Jefferson, Johnson, Story, Hamilton, Appanoose, Decatur, Ringgold, 

 Taylor, Harrison, Woodbury, and Emmet counties. 



B. Leaves petioled or sessile, entire; pappus double, the inner bristles Itnuj, 

 the outer shorter. 



A. umbellatus Mill. Stem 2-8 feet high, glabrous or pubescent above, 

 striate, corymbosely branched; leaves lanceolate to oblong-lanceolate, taper 

 pointed, base narrowed into short petioles, upper sessile, usually pubescent 

 on vhe veins beneath, entire, margin hispid; heads many, in compound flat 

 corymbs; involucre campanulate or hemispheric, the scales acutish or obtns- 

 ish, in 3 or 4 rows. Low grounds; Johnson and Story counties, reported from 



