COMPOSITAE (COMPOSITE FAMILY) 795 



blunt; rays 6-13, small; achenes nearly glabrous. Dry prairies and open 

 woods, Tenn. to Man., and westw. July-Sept. 



36. S. GattingSri Chapm. Slender and strict, 4-10 dm. high ; stems smooth 

 throughout; leaves ciliolate, smooth beneath, harsh above, the lowest 0.7-1.5 

 dm. long, lance-spatulate, appressed-serrulate or subentire, the upper reduced 

 rapidly to minute entire bracts with naked axils; branches of the naked subco- 

 rymbiform panicle elongate and ascending, hardly recurved; involucre 3-4 mm. 

 long, its oblong bracts obtuse ; rays 6-10 ; achenes appressed-puberulent, or 

 glabrate below. Limestone hills and barrens, Tenn. and Mo. July-Sept. 



= = Branches of the panicle pubescent. 



a. Leaves firm and often rigid, the lower usually elongated and many times ex- 



ceeding the reduced upper ones (except in no. 39); involucral bracts thick 

 and rigid. 



1. Lower portion of the stem and the leaves essentially glabrous. 



37. S. Sh6rtii T. & G. Stem slender, simple, 0.5-1.2 m. high, minutely 

 roughish-pubescent above ; leaves (the larger 0.5-1 dm. long) oblong-lanceolate, 

 acute, the lower mostly serrate with a few fine teeth ; racemes recurved, usually 

 in a crowded panicle ; involucre slender, 4-6 mm. long ; achenes silky-pubescent. 

 Recks at the Falls of the O. 



2. Stem and leaves pubescent. 

 o Stems and leaves ashy or whitish with close puberulence. 



38. S. nemoralis Ait. Clothed with minute grayish-hoary soft or roughish 

 pubescence ; stem simple or corymbed above, 1.5-7.5 dm. high ; leaves oblan- 

 ceolate or spatulate-oblong , mostly subtending axillary fascicles ; the lower long- 

 petioled, usually crenate-toothed, 5-15 cm. long ; the uppermost greatly reduced, 

 1-3 cm. long ; racemes numerous, dense, at length recurved, and ordinarily form- 

 ing a crowded compound raceme or panicle which is turned to one side ; invo- 

 lucre 3.5-6 mm. long, its firm yellowish bracts linear-oblong, appressed ; rays 

 5-9, bright yellow. Dry open soil (rarely in woods J, P. E. I. to the Saskatche- 

 wan, and south w. July-Nov. (rarely Dec.). 



39. S. m611is Bartl. Stout, rigid, canescent; the stems 1.5-5 dm. high, soli- 

 tary or clustered from & freely stoloniferous subligneous base; leaves rigid, oval 

 or oblong, obtuse or rarely acutish, gradually reduced upward, the uppermost 

 1-3 cm. long, the lower 3-8 cm. long; racemes ascending in a dense thyrse; 

 involucre 4-6 mm. long, greenish-yellow. (S. nemoralis, var. incana Gray.) 

 Dry hills and plains, Man. and Minn., westw. and south w. July-Sept. (Mex.) 



o o Stems and leaves green. 



40. S. radula Nutt. Stem and oblong or obovate-spatulate leaves rigid and 

 very rough, not hoary, the upper leaves sessile ; bracts oblong, rigid ; rays 3-6 ; 

 otherwise nearly as in no. 39. Limestone bluffs and dry open soil. s. w. 111. to 

 w. La. and Tex. Aug. -Oct. 



b. Leaves thinner, essentially uniform from base to summit of the stem ; invo- 



lucral bracts thin. 



1. Leaves elongate, linear to lance-oblong. 

 o Involucre 2-2.8 mm. long. 



41. S. canadSnsis L. Stem rather slender, 0.3-1.5 m. high, glabrous at least 

 below, often minutely pubescent above ; leaves narrowly lanceolate, thin, gla- 

 brous above, minutely pubescent on the nerves beneath, mostly sharp-serrate, the 

 middle ones 6-13 cm. long, 5-18 mm. wide ; heads tiny; crowded in recurved 

 racemes and forming dense broadly pyramidal panicles ; pedicels strongly pilose ; 

 involucral bracts linear, mostly attenuate, greenish-straw-color. (Var. glabrata 

 Porter.) Thickets and rich open soil, Nfd. to N. Dak., s. to W. Va. and Ky. 

 July-Sept. 



Var. gilvocanSscens Rydb. Stems and leaves cinereous or canescent with 

 minute puberulence; leaves broadly lanceolate to lance-oblong, the middle ones 



