coMPOsiTJi. (composite family.) 251 



*+ ++ Leaves more or less plainln 3-ribhed ; heads in one-sided spreading or re- 

 curved racemes, J arming an ample j>anicle. Not maritime. 

 = Smooth and glabrous, at least the stem and bright green leaves, 

 ci. Leaves ^firm and rather rigid ; involucral scales thickish, obtuse, quite unequal. 



29. S. Missouriensis, Nutt. Smooth throughout (l -3° high); leaves 

 linear-lanceolate, or the lower hroadly lanceolate, tapering to both ends, with 

 very rough margins; teeth, if any, sharp and rigid; heads and dense crowded 

 racemes nearly as in n. 28 ; achenes nearlg glabrous. — Dry prairies, from Wise, 

 and Ind. south and westward. — Heads \\-2" long. 



30. S. Shortii, Torr. & Gray. Stem slender, simple (2-4° high), mi- 

 nutely roughish-pubescent above; leaves (the larger 2-3' long) oblong-lance- 

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

 short in a crowded panicle; achenes silkg-pubescent. — Rocks at the Falls of 

 the Ohio ; Ark. — A handsome species ; heads 3" long, narrow. 



b. Leaves thinner ; involucral scales thin, chiefly linear, obtuse. 



31. S. serotina, Ait. Stem stont (2-7° high), smooth, often glaucous; 

 leaves quite smooth both sides, lanceolate, taper-pointed, very sharply serrate, 

 except the narrowed base, rough-ciliate ; the ample panicle pubescent ; raijs 

 7 -\4, 7-ather long. (S. gigantea, of previous ed.) — Copses and fence-roAvs; 

 common, and presenting many varieties. Seldom very tall. 



Var. gigantea, Gray. Commonly tall, 5-8° high ; leaves more or less 

 pubescent or hispidulous beneath. (S. gigantea, Ait.; S. serotina of previous 

 ed.) — Thickets and low^ grounds, Can. to Tex. 



32. S. rupestris, Raf. Stem smooth, slender, 2-3° high; leaves linear- 

 lanceolate, tapering both wags, entire or nearly so ; panicle narrow ; heads very 

 small ; rays 4-6, very short. — Rocky river-banks, W. Va. to Ky. and Ind. 



= = Pubescent (at least the stem) or hispidulous-scabrous. 



33. S. Canadensis, L. Stem rough-hairy, taW and stout (3-6° high); 

 leaves lanceolate, pointed, sharply serrate (sometimes almost entire), more or 

 less pubescent beneath and rough above ; heads smcdl ; rays very short. — Borders 

 of thickets and fields; very common. — Varies greatly in the roughness and 

 hairiness of the stem and leaves, the latter oblong-lanceolate or elongated 

 linear-lanceolate; — in var. pr6cera, whitish-woolly underneath; and in var. 

 scXbra also very rough al)Ove, often entire, and rugose-veined. 



34. S. nemoralis, Ait. Clothed with a minute and close grayish-hoary 

 (soft or roughish) pubescence ; stem simple orcorymbed at the summit (^-2^° 

 high) ; leaves oblanceolafe or spatulate-oblong, the lower somewhat crenate- 

 toothed and tapering into a petiole ; racemes numerous, dense, at length re- 

 curved, forming a large and crowded compound raceme or panicle which is 

 usually turned to one side; scales of the involucre linear-oblong, appressed; 

 rays 5-9. — Dry sterile fields; very common. Flowers very bright yellow, 

 beginning early in Aug. — Var. incana, Gray, of Minn., and westward, is a 

 dwarf form, with rigid oval or oblong leaves, rather strongly serrate or entire, 

 and the clusters of heads in a dense oblong or conical thyrse. 



35. S, radula, Nutt. Stem and oblong or oborate-spatulate leaves rigid 

 and very rough, not hoary, the upper sessile; scales oblong, rigid; rays 3-6; 

 otherwise nearly as in n. 34. — Dry hills, W. 111., Minn.. Kan., and southward. 



