Obdm 70.— composite. 44^ 



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

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

 disk abortive ; pappus a small, 2 to 3-toothed crown. — 21 A little pros- 

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

 Vernal fls. 



b. Virginidnum L. — In rich shady soils, .Md. to 111., common southward to the 

 Gulf. One of the earliest flowers of spring. Plant flat on the ground, Inreute, 

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

 a petiole, creuate. Bays 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 cani- 

 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. — 2f Stout, coarse, resinous herbs. Hds. large. 

 Fls. yellow. 



* stem nearly Icafles-s scape-like. Lvs. very large, alternate, mostly radical Nob. I — 3 



* Stemleal'y. — Leaves verticillata in whorls of 8s, rarely 4s Noa. 4, Gp 



— Leaves opposite, rarely the highest scattered Nos. 5 — 7 



— Leaves alternate (the lowest opposite oi- verticillate or alternate) No. S 



— Leaves connate-perfoUate No. 9 



1 S. lacini^tuzii L. Polar Plant. Very rough, with white, hispid hairs; lvs. 

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

 hds. spioate, distant; scales ovate, a^pendaged and squarrous at apex, — ^^Vestem 

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

 pious resin. Stem 3 — lOf liigh. Lower lvs. 1 — 2f long, much divided, resem- 

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

 Jl.— Sept. 



2 S. terebinthiniceum L. Prairie Bniux)CK. St and ped. glabrous ; lvs- 

 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, 1 — 16' wide. Involucre 

 globous. Hds. 1' diam., rays 1' long. Achenia narrowly 2-winged. JI — Sept. 



/3i- PINNA TiFlDUM. Lvs. more or less deeply lobed or pinnatifid. — Prsiiries, etc., 

 with the other form. (S. pinnatilidum EU.) 



3 S. dompositum Mx. Glabrous throughout; st. slender, almost naked, glau- 

 cous ; lvs. radical, on long petioles, deeply sinuate-pinnatifid, the segments sinuate- 

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

 roundish-obovate ; rays about 10. — Barrens, N. Car. to Pla. (Peay). St. 3 to 6f 

 high. Hds. 1" diam., about 10-rayed, rays about as long (4'') as the involucre. 

 Jan. — Aug.' 



/?. RENIFOEME. Lvs. roundisli or reniform, cordate, slightly sinuate-lobed or 

 toothed. — Upper districts of Ga. and Cai'. 



i S. trifolidtum L. St. glal/rous and often glaucous, terete or G-sided ; cavline 

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

 short petioles, verticUl2Lte in 3s or is ; upper ones opposite; hds. loosely cymose, 

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

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

 4: — efhigh. — Leaves 4 — 6' by 1—2". Bays 12— 16, expanding about 2^. Ach. 

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



5 S. integrifolium Mx. Scabrous ; st. quadrangular, striate, simple ; lvs. 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 — Vf high. Leaves rigid, broad and clasping at 

 base. Heads middle-size. Rays 12 — 20. 1' in length. Ach. 4 to 6" tong, 4" 

 wide. Jl., Aug. 



