Silphium. COMPOSITE. 241 



1 -f Leaves rather few on the slender stem, the lower slender-petioled, often alternate : akenes 

 with the broad wings of the preceding. 



S. gracile, GRAY. Hispidulous: stem 12 to 30 inches high, rather naked, terminated by 

 solitary or few mostly long-pedunculate heads : leaves membranaceons, ovate-oblong or ob- 

 long-lanceolate, acute at both ends, denticulate ; radical and lower cauliue ample (5 to 9 

 inches long) ; upper cauliue from 2 inches to half-inch long : involucre of nearly equal and 

 rather few oblong bracts: akenes orbicular or very broadly oval, broadly winged, and with 

 a comparatively shallow notch. Proc. Am. Acad. viii. G53. Prairies of Middle Texas, 

 Drummond, Lindhcimtr, Hall, &c. Sometimes the leaves are all alternate and the petioles 

 of the one or two principal cauline 2 or 3 inches loug, equalling the blade. 



i ) -t Leaves numerous on the stem, varying from opposite to alternate or the middle ones 

 verticillate, only upper and alternate ones (if any) strictly sessile by a broad base: akenes with 

 narrow wings and a comparatively shallow open notch; awn-like pappus-teeth usually evident 

 and not rarely partly separate from the wing. 



S. AsteriSGUS, L. Stem 2 to 4 feet high, commonly hispid : leaves from ovate-oblong to 

 oblong-lanceolate, coarsely and irregularly dentate or serrate, or some entire, scabro-hispid- 

 ulous or hispid, all the upper not rarely alternate, seldom any verticillate ; upper commonly 

 sessile by a rounded or partly clasping base ; lower short-petioled : heads solitary or few on 

 leafy branches : involucre foliaceous and squarrose (half-inch high), hirsute or hispiclulous : 

 akenes obovate-oval. Spec. ii. 920 (Dill. Elth. t. 37, f. 42) ; Michx. Fl. ii. 14G; DC. Prodr. 

 v. 512 ; Torr. & Gray, Fl. ii. 278. Dry sandy soil, common from Virginia and Tennessee 

 to Florida and Louisiana. 



Var. Icevicaule, DC., 1. c. Stem smooth and glabrous, either throughout or up to the 

 branches. Torr. & Gray, 1. c. S. scabrum, Walt. Car. 217. S. reticulatum, Moeuch, Meth. 

 607, fide syu. L. S. Asteriscus, var. scabrum, Nutt. Geu. ii. 183. S. dentatum, Ell. Sk. ii. 468 ; 

 Torr. & Gray, 1. c. S. lanceolatum, Nutt. Trans. Am. Phil. Soc. vii. 341, a narrow-leaved 

 form. .S 1 . Asteriscus, var. dentatum, Chapm. Fl. 221. S. Carolina to Georgia and Alabama. 



S. trifoliatum, L., 1. c. Stem 4 to 7 feet high, very smooth and glabrous, terminated by 

 naked corymbiform panicles of numerous usually slender-peduncled heads : leaves lanceo- 

 late, varying to oblong ovate, and from entire to sparsely serrate, from almost glabrous and 

 smooth to scabrous or hispidulous-pubescent, seldom alternate, a part of them usually 3-4- 

 nately verticillate, commonly acute at base and the upper subsessile, lower tapering into 

 margined petioles : involucre somewhat campanulate, narrower and usually smaller than in 

 the foregoing ; the bracts hardly foliaceous, smooth and glabrous, except the ciliate margins : 

 akenes broadly obovate-oval. Hook. Bot. Mag. t. 3355 ; Torr. & Gray, 1. c. S. trifoliatum, 

 ternatitm, & atropurpurcum, Retz in Willd. Spec. iii. 2333. S. ternifolium, Michx. Fl. ii. 146. 



Dry woodlands, Penn. and Ohio, and through the upper country to Alabama. 



Var. latifolium. Stem 2 to 4 feet high : leaves broader, seldom more than opposite : 

 heads fewer and broader. S. lai-irjatum, Ell. Sk. ii. 465 (perhaps Pursh, Fl. ii. 578, but his 

 character points to S. intcgri folium) ; Torr. & Gray, 1. c. W. Georgia, Alabama, and low- 

 country of S. Carolina ; and broad-leaved northern forms are similar. 



* * * Stem terete, almost leafless and scapiform, bearing a loose panicle of slender pedunculate 

 heads : involucre nearly hemispherical, of rounded mostly erect and coriaceo-hcrbaceous bracts: 

 radical leaves ample, long-petioled, cordate at base: cauline when present all alternate and 

 slender-petioled : herbage almost glabrous and smooth, or the leaves hispidulous and papillose- 

 scabrous. (True KOSIN-WKKDS.) 



S. COmpositum, MICHX. Stem slender, 2 to 6 feet high, commonly glaucous : radical 

 leaves of roundish-cordate or reuiform or more ovate circumscription, 6 to 12 inches long or 

 broad: heads small and numerous: involucre a third or rarely half inch high: rays small 

 and scattered, 4 lines long : akenes roundish-obovate and with wing broadened above, so as to 

 form a deep notch, with which the two subulate pappus-teeth are confluent, sometimes nar- 

 rowly winged so that the summit is barely emarginate and minute pappus-teeth nearly free. 



Torr. & Gray, Fl. ii. 276. The first-described form (var. Michnuxii, & var. oratifolinm, Torr. 

 & Gray,l. c.) has the leaves varying from deeply sinuate-pinnatind to pinnately or somewhat 

 ternately divided into 3 to 7 divisions, which are again sinuate-lobed ; for this the specific 

 name is appropriate, being S. compositam, Michx. Fl. ii. 145 ; Ell. 1. c. ; DC. 1. c., and 5. la- 

 ciniatum, Walt. Car. 217, not. L. S. nudicanle., M. A. Curtis in Bost. Jour. Nat. Hist. i. 127, 



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