COMPOSITE. , 141 



1. S. canadensis, L. 



Stem stout, 1-3 ft. high; leaves lanceolate, 3-nerved, pointed at each 

 end, serrate for half their length, or the uppermost entire, minutely pubes- 

 cent ; heads in dense, somewhat one-sided recurving axillary racemes crowded 

 in a close pyramidal spike; pedicels hairy. Moist or rich soil, Man.-Alta., 

 variable. 



2. S. graminifdlia, Salisb. 



Stem rather slender, leafy, 1-3 ft. high, glabrous; leaves lance-linear, 

 glabrous, minutely pubescent and roughened on the edges; head's small, 

 8-12-flowered, gathered in short close clusters, each cluster on the end of a 

 flowering branch, the branches all rising to about the same height, and the 

 whole forming a fiat-topped corymb-like cyme; bracts of the involucre 

 yellowish. (S. lanceolata, L.) Moist soil, Man.-Alta. 



3. S. rlgida, L. 



Stem stout, 1-2 ft. high, rough and somewhat hoary-pubescent through- 

 out; leaves oblong, pinnately veined, thick and rigid, the lower petioled, 

 the upper sessile on a broad base; heads many-flowered, collected in a dense 

 round-topped cyme. Dry prairie, Man.-Alta. 



4. S. serotina. Ait. , ' 



Stem stout, 2-6 ft. high, glabrous; leaves lanceolate to oblong, thin, 

 glabrous, sharply serrate except at the base, or the uppermost nearly en- 

 tire ; head3 crowded on recurving or spreading branches which unite to form 

 a large, often leafy, pubescent panicle. Moist soil, Alta. 



5. S. deciimbens, Grepne. 



Stems decumbent, 4-16 in. high, clustered, from a strong perennial root, 

 usually dark reddish; lower leaves spatulate to oblanceolate, serrate towards 

 the apex ; stem leaves much reduced ; heads large, in a somewhat interrupted 

 panicle. Rocky Mts. and eastward. ' 



6. ,S. oreSphila, Rydb. 



Resembling the preceding but a larger form and usually found at lower 

 levels. Alta. , > 



7. S. jfincea. Ait. , 



Smoo'th, erect, 1-3 ft. high; lower leaves elliptical to oval, serrate, taper- 

 ing into petioles; stem leaves narrower, 3-nerved, the upper entire; racemes 

 crowded in a conical, usually curved panicle. About thickets, Man.-Alta. 



