79G coMPOSiTAE (composite family) 



4-7 cm. long, 1-2 cm. broad. — Dry or sterile situations, Gasp6 Co., Que.; and 

 from 111. to Man.. Kan., and westw. 



42. S. rupestris Raf. Stem smooth, slender, 5-10 dm. high ; leaven linear- 

 lanceolate, taiieriiig both ways, entire or nearly so, glabrous upon both surfaces ; 

 racf^mes ascendimj, scarcely recurved, forniiny somevihat oj)en or elongate pan- 

 icles ; pedicels slightly pilose or glabrate. — Rocky river-banks, W. Va.., Ky., 

 and Ind. Aug., Sept. — Too near the preceding, of which it may be a variety. 



o o Involucre 3.2-5 mm. long. 



+ Stem closely and minutely pubescent throughoiit. 



43. S. altissima L. Stem cinereous-puherulent, stout, 0.7-2 m. high ; leaves 

 thickish, lanceolate, subentire or more or less toothed, minutely pubescent or 

 scabrous above, short-pilose beneath, the middle ones 0-13 cm. long, 10-18 mm. 

 broad ; heads crowded in recurved racemes forming dense high broad'y pyram- 

 idal panicles ; involucre 3.2-4.5 mm. long., its subherl)aceous bracts linear. 

 {S. canadensis Man. ed. 0, in part, including var. scabra T. & G.) — Rich open 

 ground, Aroostook valley. Me.; Mass. and Vt. to Mich., Kan., and south w. 

 Aug .-Oct. 



Var. procera (Ait.) Fernald. Stem and lower surface of the leaves more 

 loosely pubescent with distinct soft hairs ; branches of the panicle strongly 

 ascending, scarcely if at all recurved at tip. («S'. procera Ait.; S. canadensis, 

 var. T. & G.) — A little kno^vn extreme, apparently best developed in the 

 L. Superior region. — In inflorescence simulating S. elongata Nutt, of the North- 

 west and of the lower St. Lawrence, which has glabrous or glabrate stems and 

 leaves, and less herbaceous involucre. 



-f + Stem glabrous throughout (or except in the inflorescence). 



44. S. ser6tina Ait. Stem stout, 0.5-2.5 m. high, smooth, often glaucous; 

 leaves quite smooth both sides, lanceolate to oblanceolate, taper-pointed, very 

 sharply serrate, except the narrowed base, rough-ciliate ; the middle ones 7-16 

 cm. long, 1-^3 cm. wide ; the ample panicle pubescent ; involucre 3.5-5 mm. long, 

 its bracts linear, subherbaceous ; rays 7-14, rather long. — Thickets, in rich soil, 

 N. R. to B. C, and south w. July-Sept. 



Var. gigantea (Ait.) Gray. Leaves glabrous above, slightly pubescent be- 

 neath, especially on the nerves; involucre 3.2-4 mm. long. — Low ground, 

 e. Que. to 111., and south w. 



2. Leaves broad-elliptic or -ovate. 



45. S. Drumm6ndii T. & G. Stem (3-9 dm. high) a7id lower surface of the 

 broadly ovate or oval somewhat triple-ribbed leaves minutely velvety-pubescent, 

 some of the leaves almo.st entire ; racemes panicled ; bracts of the involucre 

 oblong, obtuse; rays 4 or 5. — Limestone cliffs and rocky woods, s. w. 111. and 

 Mo. to La. Sept., Oct. 



-*-•*- ^- +- Heads in a compound, corymb terminating the simple stem, not at all 

 racemose ; leaves mostly with a strong midrib. 



++ Leaves flat, not '^-nerved. 



46. S. rigida L. Bough and someiohat hoary with a minute jDubescence ; 

 stem stout. 0.3-1.5 m. high, very leafy ; leaves oval or oblong, copiously feather- 

 veined, thick and rigid, the basal 1-3 dm. long, petioled ; the upper closely ses- 

 sile by a broad base, slightly serrate, the uppermost entire ; corymb dense ; 

 heads more than HO-floicered ; the involucre 6-8 mm. long ; rays 7-10. — Dry soil. 

 Mass. to Man., and .south w. Aug.-Oct. 



47. S. ohioensis Riddell. Very smooth throughout; stem wand-like, slen- 

 der, leafy, 6-!» dm. high ; stem-leaves oblong-lanrool ate, flat, entire, rough-mar- 

 gined, obscurely featlier-veined, closely ses.sile, tlie upper only 3-4 cm. long ; 

 the lower and radical ones elongated, 3 dm. long, slightly serrate toward the 

 apex, tapering into long margined petioles ; heads numerous, on smooth pedicels, 

 W-IO-flowered ; the involucre 4.5-6 mm. long ; rays 6 or 7. — Swamps and wet 

 prairies, Ont. and w, N. V. to Ind. and Wise. Aug., Sept. 



