ORDER LXVIII. COMPOSITE. 381 



Genus XXXV.— SILPH'IUM. L. 

 (From silphion, a name of an ancient plant, transferred to this genus.) 



Involucre leafy, squarrose. Ray florets pistillate, those of 

 the disk staminate. Seed compressed, obcurdate, emarginate, 

 2-toothed. Receptacle chaffy. 



1. S. lacinia'tum, (L.) Stem hispid, simple, nearly glabrous toward 

 the base. Leaves alternate, about 2 feet long and 1 wide, pinnatifid, 

 the segments toothed and sinuate, scabrous. Involucre consisting of 10 

 leaves, subulate. Ray florets numerous, about as long as the involucre. 

 Pappus 2 small awns. — Yellow. 2£. Aug. — Sept. Western Georgia 

 and Alabatua. 8 — 12 feet. 



2. S. pinnatifi dum, (Ell.) Stem glabrous. Leaves large, pinnatifid, 

 sinuate ; segments usually acute, upper surface glabrous, the under 

 slightly scabrous. Flowers in panicles, large ; involucre glabrous, with 

 the exterior leaves orbicular, the interior oval. — Yellow. If. July. 

 Western Geo. and Ala. 4 — 6 feet. 



3. 8. compos'itum. (Mich.) Stem glabrous. Leaves irregularly lobed, 

 sinuate, sometimes pinnatifid, glabrous above, somewhat hairy beneath. 

 Fcuitrs in terminal panicles; involucre with the leaves slightly ciliate. 

 — Yellow. If. May — Aug. Pine-barrens. 2 — 3 feet. 



4. 9i terebinthtna CECM, (L.) Stem, erect, glabrous. Radical leaves 

 cordate or nearly orbicular, or reniform, sometimes lobed and dentate ; 

 cauline ones alternate, serrate, scabrous, ovate. Flowers numerous, in 

 corymbose panicles; exterior leaves of the involucre ovate, acute, the 

 interior obtuse ; ray florets 10 — 12. — Y'ellow. 2J. July — Aug. Moun- 

 tains. 4 — 5 feet. 



5. S. trifolia'tcm, (L.) Stem glabrous, somewhat hexagonal, usu dly 

 purple. Leaves ovate-lanceolate, serrulate, slightly scabious on the 

 upper surface, glabrous beneath, the upper ones nearly sessile, the 

 lower ternate. Flowers in terminal corymbs; involucre with ovate, 

 ciliate, loosely appressed leaves; ray florets about 14. — Y'eliow. 2f. 

 Aug. — Oct Mountains. 4 — 5 feet. 



6. S. tep.na'tl'm. Stem terete, or slightly angled, glabrous. Leave* 



verticillate, by threes, lanceolate, acute, denticulate or serrate, slightly 

 scabrous on the upper surface, pubescent along the veins beneath. 

 F lo w er* in terminal corymbs; involucre ciliate, with ovate, loosely ap- 

 pressed leaves; ray florets 12 — 14, long. — Yellow. 2f. Aug.— Oct. 

 Mountains. 4 — 6 feet. 



7 Sb ateoplrpc'eeum. Stem erect, terete, purple, glabrous. Leaven 

 mostly verticillate, by fours, numerous, the lower ones alternate, and 

 the uppermost scattered, the intermediate ones sometimes by threes ; 

 all lanceolate, scabrous, dentate, on ciliate petioles; midrib purple. 

 Flowers in dichotomous panicles; involucre ciliate, with ovate scales; 

 ray florets long, narrow. — Yellow. If. Aug. — Sept. Upper districts. 

 4 — 5 feet. 



S. S. denta'tum, (Ell.) Stem erect, purple, glabrous. Leaves broad- 

 lanceolate, sinuate, toothed, hairy, scabrous, the lower ones opposite, 

 upper ones alternate, sessile. Flowers in terminal corymbs ; involucre 

 ciliate, with broad-ovate leaves ; ray florets about 10, ova!. — Yellow. 

 A '.:_". — Sept. Common, near Culloden. 2 — 3 ft. 



