COMPOSITE. (COMI'OSITi: FAMILY.) 249 



♦ Stem trrrtr, miked ahnrr, nltrrnatr-lrtivnl near the hnsn {root irnj larrjf and thick). 



1. S. laciniitum, L. (Hosix-wkkd. Compass-I'laxt.) Ronfj/i-hrislhi 

 ihroiirilioHt ; stciii stout (.■!° - G° lii^li), leafy to the top; ledvcs jiinmitdi/ pnrtij, 

 potiolcd l)ut dilated and claspiiij,' at the base; t/ieir dinsloiis lanreolate or /iiii"ir, 

 sicwtc, riil-lolii'd or pliinatl/id, rarely entire; heads few (!'- 2' broad), somewhat 

 raecnied ; srtifes of the involiicro orate, tapcriug into loiicj and s/neadinrj ri(fid jioinli ; 

 aehcnia broadly winjjed and deeply notehed. — Prairies, Miehij^an and Wiscon- 

 sin, thence southward and westward. July. — Lower and root-leaves vertical, 

 12 -30' lon<;, ovivtc in outline; on the wide open prairies disposed to present 

 their edi^es noith and south ; hence called Conipasa-Plant. 



•2. S. terebinthiniceura, L. (Tijaiuie Dock.) Stem smooth, slender 

 (4°- 10° hi;;h), panicled at the sununit and bearing nuiny (small) heads, leafless 

 except towards the base ; leaves orate and ovate-oblong-, somewhat heart-shaped, 

 serrate-loot lied, thick, rough, especially beneath (1° - 2° long, on slender petioles) ; 

 scales of the inrotucre roundish, obtuse, smooth; aehenia narrowly wingeii, slightly 

 notched and 2-toothed. — Var. piNNATfriDUM has the leaves deeply cut or pin- 

 natilid, but varies into the ordinary form. — Prairies and oak-openings, Ohio 

 and Michigan to Wisconsin and southward. July- Sept. 



* * Stem terete or slii/htiij 4-anffled, leaf}/: leaves undivided (not larr/e). 



3. S. trifoli^tum, L. Stem smof>th, often glaucous, rather slender (4°- 6° 

 high), branched aliove; stem-leaver liinetolate, /w/»W, ?«<//•« or scarcely ser>*ate, 

 rough, shoit-fietioled, in whorls o/' 3 or 4, the ii])perniost opposite; heails loosely 

 panicled; aehcnia rather broadly winged, and sharply 2-toothed at the top. — 

 Dry plains and banks, W. New York to Wisconsin and southward. Aug. 



4. S. AsterisCUS, L. Stem hispid (2° -4° high); leaves opposite, or the. 

 loiver in whorls of 3, the upper alternate, oblonc] or oval-lanceolate, coarseli/ tootlw.d, 

 rarely entire, romjh-huirif ; heads nearly solitary (large); aehcnia obovate, 

 winged, 2-to()thed. — Dry sandy soil, Virginia and southward. 



5. S. integrifdliura, Michx. Stem rouyh, rather stout (2° -4° high), 

 rigid, 4-angular and grooved ; leaves all opposite, rigid, lanccoluie-orate, entire, 

 tapering to a sharj) \)oint from a roundish /uart-shapcd and parlli/ clasping Imse, 

 rough-pubescent or nearly smooth, thick (3' - 5' long) ; heads m a close forking 

 corymb, short-pcduncled ; aehenia broadly winged, deeply notched. — Var. 

 L/EVE ha-s the stem antl leaves smooth or nearly so. — Prairies, Michigan to 

 Wisconsin, and southward. Aug. 



« * « Stem square: leaves opposite, connate (thin and large, G'-l.')' lonq). 



6. S. perfoliatum, L. ((-li'-Pi,ant.) Stem stout, often branched alwro 

 (4° -8° high) ; leaves ovate, coarsely toothed, the upper united by their bases 

 and forming a cup-shaped disk, the lower abruptly narrowed into winged petioles 

 which are (onnate by their bases; heads corymbose ; aehenia wingeil and vari- 

 ously notched. — Huh soil along streams, Michigan to Wisconsin, and south- 

 ward : common. Also escaped from gardens eastward. July. 



28. PARTHENIUM, L. Paktukmi m. 



Heads many-tlowcred, inc(Mis))i(uou>ly radiate ; the ."> ray-(lowers with verr 

 short and broad obcordate lii;ules not jirojecting beyond the woolly disk, pistil- 



