Thistle Family. 75 



E. altissimum L. Stem simple, 2-6 feet high, soft-pubescent, leafy; leaves 

 opposite, sessile, lanceolate, tapering 1 both ways, conspicuously 3-nerved, en- 

 tire or toothed beyond the middle; involucral scales oblong-, shorter than the 

 heads, in about two rows, outer shorter; heads 1-5-flowered. Dry ground; 

 August^September; frequent; eastern and southeastern counties, sparingly 

 westward; Winneshiek, Benton, Fayette, Muscatine, Des Moines, Henry, 

 Johnson, Story, Decatur, and Harrison counties. 



E. serotinum Mx. Stem 3-6 feel, high, usually branched, soft-puberulent, 

 leaves mostly opposite, a few upper alternate, long-petioled, ovate-lanceolate, 

 3-nerved, coarsely serrate; heads 12-15-flowered, in compound corymbs; in- 

 volucre pubescent; scales obtuse. Low ground; August-September, infre- 

 quent; Fayette, Scott, Muscatine, and Woodbury counties. 



E. perfoliatum L. Boncxet. Stem 2-4 feet high, hairy, corymbosely 

 branched; leaves opposite or in 3's, connate-perfoliate, lanceolate, pointed, 

 crenate-serrate, downy beneath; heads 10-15-flowered, in a dense corymb, 

 scales narrowly lanceolate, shorter than the flower. Low grounds; August; 

 common. The number of flowers in the head and the connate character of 

 the leaves vary greatly. 



E. ageratoides L. White Snalse-root. Stem smooth, simple or branched, 1- 

 3 feet high; leaves opposite, petioled, thin, broadly ovate, pointed, 3-nerved, 

 large toothed; heads 10-30-flowered, in a compound corymb, involucral scales 

 in one row, oblong, obtuse. Woods; July-September; common. 



E. coelestinum L. Mist-flower. Plant pubescent or puberulent, 1-3 feet 

 high; leaves opposite, ovate, petioled, acute or obtuse, crenate-dentate, base 

 truncate or slightly cordate; heads cymose-eorymbose; flowers blue or violet. 

 Moist soil; August-September; reported from Lee county by Arthur. 



hyUHNIA L. Perennials. Heads paniculate-corymbose, cream colored, dis- 

 coid, 10-20-flowered. Involucral scales narrowly linear, loosely imbricated, 

 parallel nerved. Pappus a row of white plumose capillary bristles. Achenes 

 cylindrical, 10-striate. 



K,- eupatorioidcs L. Stem 2-3 feet high, erect, usually simple, minutely 

 pubescent, leaves alternate, the upper sessile, the lower short-petioled, lanceo- 

 late or linear-lanceolate, entire or sparingly dentate, acuminate. Dry soil, 

 August-September; common. 



r\. glutinosa Ell. Usually taller and stouter than the preceding, pubes- 

 cent or tomentulose; leaves all sessile, lanceolate to Ovate-lanceolate, sharply 

 serrate, those of the branches linear-lanceolate and entire; heads numerous, 

 densely clustered in cymes. Dry soil; August-September; reported from 

 Fayette and Story counties; probably common. (K. eupatorioidcs corymbulosa 

 T. & G.) 



LIATR.IS Schreb. Button Snakeroot. Blazing-Star. Perennials, from 

 a roundish corm, erect, simple, leafy. Leaves long-linear, entire, rigid, ses- 

 sile, or lower oblong-lanceolate or oblong-ovate, petioled. Heads discoid, few 

 to many-flowered. Involucral scales well imbricated in many rows. Recep- 

 tacle naked. Pappus of from 15-40 capillary bristles. Achenes slender, tap- 

 ering, 10-ribbed. 



* Involucre cylindric or turbinate, 15-16-flowered. 



L. squarrosa (L.) Willd. Stem 1-3 feet high; frequently hairy; leaves 

 rigid, long-linear; heads few, racemose, about an inch in length; involucral 

 scales tapering to an acute point, leaf-like, spreading; corolla-lobes hairy in- 

 side, pappus plumose. Prairie soil; August-September; Scott, Wapello, 



