COMPOSITAE (COMPOSITE FAMILY) 853 



d. Stems mostly leafy below, nearly naked above ; leaves variable ; 

 the lower ovate, obovate, or oblanceolate ; the upper much 

 reduced, often bract-like e. 



6. Pubescence when present floccose-lanate and confined chiefly 

 to the base of the stem and to the leaf-axils /. 



/. Heads discoid 7. & discoideus. 



f. Heads radiate (except in S. obovatus, var. elongatus) g. 

 g. Lower leaves obovate, occasionally subrotund or oblong ; 



stolons when well developed slender and creeping . 8. & obovatus. 

 g. Lower leaves subrotund to lanceolate ; the earliest leaves 

 ordate or subeordate^ usually long-petioled ; stolons 

 short and stout, assurgent. 

 Basal leaves all broad-ovate, deeply cordate and relatively 



large . . . 9. S. aureus. 



Basal leaves mostly lanceolate ; onlv the earliest ones 



subrotund, cordate, and relatively small . . .10. S. Robbinsii. 

 g. Lower leaves oblong-oblanceolate to spatulate, usually 

 narrowed gradually at the base ; the earliest rarely 

 subrotund or oblong. 



Stem but slightly woolly at the base, comparatively few- 

 headed 11. S. Balsamitae. 



Stern rather densely and permanently woolly at the base ; 



heads usually numerous 12. S. Smallii. 



0. Pubescence white-lanate and more or less persistent over stem 



and leaves (rarely in no. 13 completely absent). 

 Basal leaves subrotund-ovate to oblong-lanceolate. 



Stem-leaves deeply and irregularly divided . . .13. S. plattensis. 

 Stem-leaves usually dentate, not deeply divided, only a 



few at most lyrate 14. S. tomentosus. 



Basal leaves oblong-obovate, oblanceolate, or spatulate. 



Eastern species 15. S. antennariifolius. 



Western species 16. S. canus. 



e. Pubescence of crisp-hirsute or subvillous hairs, not floccose 



or lanate, rarely quite glabrous . . . . . . IT. S. integerrimux. 



G. Heads larger, 1.5-2 cm. high during anthesis . . . . 18. S. Pseudo-Arnica. 



1. S. VDLGA.RIS L. (COMMON GROUNDSEL.) Low annual, 1-5 dm. high, 

 corymbosely branched, glabrate, leafy to the inflorescence ; leaves pinnatifid 

 and toothed, 1-8 cm. long, 0.5-3 cm. broad ; calyculate bracts (bracteoles) of 

 the involucre distinctly black-tipped ; rays none ; achenes hirtellous. Waste 

 grounds, common. July-Sept. (Nat. from Eu.) 



2. S. visc6sus L. Coarser, 1.5-4 dm. high, viscid-pubescent and heavy- 

 scented ; leaves pinnatifid with toothed segments or 2-pinnatifid, 2-10 cm. long, 

 0.5-5 cm. broad ; calyculate bracts (bracteoles) of the involucre not black-tipped ; 

 rays minute, bright yellow. Waste grounds, coast of e. Que. to N. E.; also on 

 ballast near Philadelphia. July-Sept. (Nat. from Eu.) 



3. S. sYLvAxicus L. Stem erect, 1-7 dm. high, simple or branched, some- 

 what pubescent ; lower leaves petioled and more or less lyrate, the upper pin- 

 natifid with unequal lobes, sessile and sagittate at the clasping base, 2-15 cm. 

 long, 1-8 cm. broad ; inflorescence corymbose, naked or nearly so ; heads cylin- 

 drical ; involucre barely calyculate ; ligules but slightly surpassing the disk- 

 flowers. Clearings and waste places, Nfd. and e. Que. to Me., chiefly near the 

 coast ; also near Painesville, O. July-Sept. (Nat. from Eu. ) 



4. S. palustris (L.) Hook. Annual or biennial, loosely villous to nearly gla- 

 brous ; stem stout, 2-7 dm. high ; leaves oblong-lanceolate, irregularly toothed 

 or laciniate, the upper with a heart-shaped clasping base ; rays 20 or more, 

 short, pale yellow ; pappus copious and becoming very long. Wet grounds, la. 

 to n. Wise., N. Dak., and north w. June-Sept. (Eu.) 



5. S. glab611us Poir. (BUTTER-WEKD.) Rather tall, 2-5 dm. or more high ; 

 leaves somewhat fleshy, lyrate or pinnately divided,' divisions crenate or cut- 

 lobed, variable ; heads less than 1 cm. high, in a naked corymbose inflorescence ; 

 rays 6-12, conspicuous. (S. lobatus Pers.) Wet grounds, N. C. to centr. 111., 

 Mo., and south w. March-June. 



6. S. JACOBAEA L. (STINKING WILLIE.) Arachnoid-tomentulose to nearly 

 glabrous ; stem erect, 2-6 dm. or more high ; basal leaves somewhat lyrate , 

 those of the stem 2-3-pinnatisect, sessile, 2-15 cm. long, 1-7 cm. broad ; inflo- 

 rescence a many-headed corymbose cyme ; heads radiate. Roadsides, pastures, 

 and ballast, Nfd. and e. Que. to Me., and locally to Ont. and N. J. July-Aug. 

 (Nat. from Eu.) 



