ORDER LXVIII. COMPOSITE. 381 



Genus XXXV.— SILPH'IUM. L. 



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



Involucre leafy, squarrose. Ray florets pistillate, those of 

 the disk staminate. Seed compressed, obcordate, einarginate, 

 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. 2f . Aug. — Sept. Western Georgia 

 and Alabama. 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. S. gompos'itum, (Mich.) Stem glabrous. Leaves irregularly lobed, 

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

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

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



4. S. terebinthina'ceum, (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. — Yellow. If. July — Aug. Moun- 

 tains. 4 — 5 feet. 



5. S. trifolia'tum, (L.) Stem glabrous, somewhat hexagonal, usually 

 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. — Yellow. If. 

 Aug. — Oct. Mountains. 4 — 5 feet. 



6. S. terna'tum. Stem terete, or slightly angled, glabrous. Leaves 

 Vert icill ate, by threes, lanceolate, acute, denticulate or serrate, slightly 

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

 Flowers in terminal corymbs; involucre ciliate, with ovate, loosely ap- 

 pressed leaves; ray florets 12 — 14, long. — Yellow. 11. Aug. — Oct. 

 Mountains. 4 — 6 feet. 



7. S. atropurpu'retjm. Stem erect, terete, purple, glabrous. Leave* 

 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. — Y'ellow. 2£. 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, oval. — Yellow. 

 11. Aug. — Sept. Common, near Culloden. 2 — 3 ft. 



