78 COMPOSITAE. 



S. serctina Ait. Stem 3-6 feet high, glabrous, often glaucous, branched 

 above; leaves lanceolate, taper-pointed, sharply serrate above the tapering 

 base, smooth on both sides, rough ciliate; panicle ample, pubescent: involu- 

 cral scales linear, obtuse; rays long-. The var. gigantka Gray has the leaves 

 more or less pubescent beneath. Open woods and borders; common; Winne- 

 shiek, Clayton, Dubuque, Muscatine, Johnson, Henry, Des Moines, Decatur, 

 Taylor, Winnebago, Dickinson, and Emmet counties; reported from Fayette, 

 Story, Hamilton, and Woodbury counties. 



S. rupestris Eaf. Stem slender, glabrous, 2-3 feet high; leaves thin, 

 linear-lanceolate, tapering both ways, entire or sparingly serrate; heads 

 small; rays short, 4-6. Loess mounds; Woodbury county, reported by Pam- 

 mel, also reported from Scott county by Nagel and Haupt. 



t t t t Leaves more or less triple-ribbed; stem pubescent. 

 S. canadensis L. Stem 3-5 feet high, pubescent; leaves lanceolate, acu- 

 minate, sharply serrate or nearly entire, pubescent beneath, rough above; 

 heads numerous, small; rays short. Borders and fields; common; varies 

 greatly; Winneshiek, Clayton, Dubuque, Floyd, Delaware, Johnson, Henry, 

 Decatur, Calhoun, Winnebago, and Emmet counties; reported from Fayette, 

 Scott, Story, Hamilton, Dickinson, Monona, and Woodbury counties. 



S. nemoralis L. Stem 6-24 inches high, cinereous-pubescent, simple or 

 corymbed above; leaves spatulate or oblanceolate, entire or the lower some- 

 what serrate and tapering into a petiole; heads small, in numerous usually 

 recurved racemes; involucral scales linear-oblong, appressed. Dry soil; com- 

 mon; Winneshiek, Dubuque, Floyd, Delaware. Johnson. Henry, Des Moines, 

 Decatur, Story, Calhoun, Winnebago, Dickinson and Emmet counties; re- 

 ported from Fayette and Hamilton counties. 



* * * Heads i?i compound corymbs or hi cymose clusters. 

 t Stem densely pubescent: 

 S. rigida L. Stem 2-4 feet high, stout, leafy, softly pubescent or scabrous; 

 leaves oval or oblong, thick, rigid, entire or obscurely serrate, feather-veined; 

 lower leaves oblanceolate, tapering into slender petioles; heads numerous, 

 large, many-flowered; involucral scales very obtuse; rays 7-10. Prairies; 

 common; Winneshiek, Floyd, Johnson, Decatur, Fremont, Jasper, Winne- 

 bago, Emmet, and Lyon counties; reported from Fayette, Seott, Story, Hamil- 

 ton, Monona, and Woodbury counties. 



f f Stem glabrous or nearly so. 

 S. riddellii Frank. Stem 1-3 feet high, glabrous, stout; leaves long and 

 narrow, entire, from a sheat!hing base, mostly recurved, radical leaves very 

 long, tapering into long petioles; heads numerous, many-flowered, in a dense 

 corymb, the branches and pedicels rough-pubescent; rays 5-7. Low prairies, 

 sloughs, often growing in water; infrequent; Muscatine, Floyd, Hancock, 

 and Emmet counties; reported from Story and Hamilton counties. 



S. lanceolata L. Stem from a long and slender rootstoek, 1-3 feet high, 

 much branched, usually smooth; leaves narrowly lanceolate, sessile, 3-nerved, 

 heads small, in sessile glomerate clusters disposed in flat-topped corymbs; 

 rays small, 15-20;'late flowering. Sandy or wet soil, pastures and copses 

 common; Johnson, Henry, Decatur, Dickinson, and Emmet counties; reported 

 from Fayette, Scott, and Story counties. (Euthamla gmmlnifnlla (L.) Nutt.) 



BOLTONIA L'Her. Bushy-branched glabrous perennials, with striate 

 angled stems, entire leaves, and Aster-like flowers. Heads many-flowered, 

 radiate; rays many, pistillate. Scales in two series,' appressed, with scarious 



