OEDEE 70. COMPOSITE. 441 



leafy, the inner chaffy ; receptacle flat, chaffy ; achenia of the ray ob- 

 compressed, obovate, each embraced by a chaff-scale ; achenia of the 

 disk abortive; pappus a small, 2 to 3-toothed crown. 2 A little pros- 

 trate herb, with opposite Ivs. and solitary, pedunculate, bright yellow- 

 vernal fls. 



C. Virginianum L. In rich shady soils, Md. to 111., common southward to the 

 Gulf. Oue of the earliest flowers of spring. Plant flat on the grout. d, hirsute, 

 at first acaulescent, at length caulescent and ascending. Lvs. ovate, tapering to 

 a petiole, creuate. Rays expanding 7 to 9 '. Feb. May. 



41. SIL'PHIUM, L. ROSIN-WEED. (The ancient name of some 

 resinous plant.) Heads many-flowered; ray-flowers numerous, in 2 or 

 3 rows, fertile, outer row ligulate ; disk-flowers sterile ; involucre cam- 

 panulate, scales in several series, leafy and spreading at summit ; recep- 

 tacle small, flat, chaffy ; achenia broad, flat, obcompressed, crowned 

 with a 2-toothed pappus. 2|! Stout, coarse, resinous herbs. Hds. large. 

 Fis. yellow. 



* Stem nearly leafless, scape-like. Lvs. very large, alternate, mostly radical Nos. 18 



* Stem leafy. Leaves verticillate in whorls of 8s, rarely 4s Nos. 4, 5 /3 



Leaves opposite, rarely the highest scattered Nos. 5 T 



Leaves alternate (the lowest opposite or verticillate or alternate) No. 3 



Leaves connate-perlbliutc No. 9 



1 S. laciniattim L. POLAE PLANT. Very rough, with white, hispid hairs; Ivs. 

 alternate. pinnat3iy parted, lower petiolate, segments sinuate-lobed or entire ; 

 hds. spicate, distant; scales ovate, appendaged and squarrous at apex. Western 

 States to Tex., producing columns of smoke in the burning prairies by its co- 

 pious resin. Stem 3 10*f high. Lower Ivs. 1 2f long, much divided, resem- 

 bling those of some thistles. Heads 4 8, very large, with large, yellow rays. 

 JL Sept: 



2 S. terebiiithinacenm L. PRAIRIE BURDOCK. St. and ped. glabrous; Ivs- 

 mostly radical, ovate and ovate-oblong, cordate, dentate-serrate, obtuse, scabrous, on 

 long petioles ; hds. few, paniculate; scales roundish and oval, glabrous, rays about 

 20. Prairies, Western and Southern States. Plant exuding resin. Stem 4 8f 

 high, nearly naked and simple. Leaves 1 2f long, 7 16' wide. Involucre 

 globous. lids. 1' diain., rays 1'long. Achenia narrowly 2 -winged. Jl. Sept. 



/3. piNNATiFiDor. Lvs. more or less deeply lobed orpinnatifid. Prairies, etc., 

 with the other form. (S. pinnatindum Ell.) 



3 S. compositum MX. Glabrous throughout; st slender, almost naked, glau- 

 cous; Zvs. radical, on long petioles, deeply sinuate-pinnatijid, the segments sinuate- 

 lobed or toothed ; hds. cory mbed, on long peduncles ; scales oval, obtuse ; ach. 

 roundish-obovate ; rays about 10. Barrens, X. Car. to Fla. (Feay). St. 3 to 6f 

 high. Hds. 7" diam., about 10-rayed, rays about as long (4'') as the involucre. 

 Jan. Aug. 



/?. RENIFORME. Lvs. roundish or reniform, cordate, slightly sinuate-lobed or 

 toothed. Upper districts of Ga. and Car. 



4 S. trifoliatuni L. St. glabrous and often glaucous, terete or 6-sided ; cavli;ie 

 Ivs. lanceolate, acute, scabrous above, smooth below, remotely dentate, on very 

 short petioles, verticiilate in 3s or 4s ; upper ones opposite; hds. loosely cymose, 

 on rather long peduncles ; scales broadly ovate, rather obtuse, smooth ; ach. oral, 

 with 2 short teeth. Dry woods and prairies, Ohio and Southern States. Stem 

 4 Gf high. Leaves 46' by 1 2". Rays 12 1C, expanding about 2'. Ach. 

 3 to 4" long, 2 to 3." wide. Aug., Sept. 



5 S. integrifcliuin MX. Scabrous ; st, quadrangular, striate, simple ; Ivs. oppo- 

 site, sessile, ovate-lanceolate, entire or slightly dentate ; hds. in a close corymb; 

 scales squarrous ; ach. roundish, broadly winged, with 2 long teeth. Western States 

 S. to Ga. Stem very rigid, 3 7f high. Leaves rigid, broad and clasping at 

 base. Heads middle-size. Rays 12 20. 1' in length. Ach. 4 to 5" long, 4" 

 wide. Jl., Aug. 



