460 COMPOSITAE, Vor. III. 
series, pistillate, fertile, the ligules numerous, linear. Disk-flowers perfect but sterile, their 
corollas tubular, 5-toothed, the style undivided. Anthers minutely 2-toothed or entire at the 
base. Achenes broad, dorsally flattened, 2-winged, notched at the apex. Pappus none, or of 
2 awns confluent with the wings of the achene. [Greek, from the resinous juice.] 
About 12 species, natives of North America, known as Rosin-weed or Rosin-plant. Type species: 
Silphium Asteriscus L. 
Stem leafy, the leaves opposite, alternate, or verticillate. 
Leaves, or their petiole-bases, connate-perfoliate ; stem square. 1. S. perfoliatum, 
Leaves not connate-perfoliate, sessile or petioled. ‘ 
Leaves opposite, or the uppermost alternate; cauline sessile. 
Leaves, or some of them, verticillate in 3’s or 4’s, petioled. 
Most or all of the leaves alternate, entire or dentate. 
Leaves all alternate, pinnatifid or bipinnatifid, large. 
_Stem leafless or nearly so, scaly above; leaves basal, large. 
Leaves sharply serrate to pinnatifid; achenes obovate. 
Leaves coarsely dentate; achenes suborbicular. 
. S.integrifolium. 
. S. trifoliatum, 
. S. Asteriscus. 
. S. laciniatum, 
. S. terebinthinaceum, 
. S. reniforme. 
NN UNbwWhd 
I. Silphium perfoliatum L. Cup- 
ay plant. Indian-cup. Fig. 4421. 
SZ 
SOAS S. perfoliatum L. Sp. Pl. Ed. 2, 1301. 1763. 
Stem square, glabrous, or rarely some- 
what hispid, branched above, or sometimes 
simple, 4°-8° high. Leaves ovate or deltoid- 
ovate, opposite, the upper connate-perfol- 
iate, the lower abruptly contracted into 
margined petioles, all thin, usually scabrous 
on both sides, or pubescent beneath, coarse- 
ly angulate-dentate, or the upper entire, the 
larger 6-12’ long, 4’-8’ wide; heads com- 
monly numerous, 2’-3’ broad; rays 20-30, 
about 1’ long and 2” wide; involucre de- 
pressed-hemispheric, its outer bracts broad, 
ovate, ciliolate, spreading or erect; achenes 
obovate, emarginate, sometimes 2-toothed. 
In moist soil, southern Ontario to Minne- 
sota, South Dakota, New Jersey, Georgia, Ne- 
braska and Louisiana. Naturalized near New 
York City, and elsewhere escaped from culti- 
vation. Called also ragged-cup. July—Sept. 
2. Silphium integrifolium Michx. Entire- 
leaved Rosin-wood. Fig. 4422. 
S. integrifolium Michx. Fl. Bor. Am. 2: 146. 1803. 
Sy specioenta Nutt. Trans. Am. Phil. Soc. (II) 7: 341. 
1841. 
Stem glabrous, rough or sometimes hirsute, co- 
rymbosely branched above, 2°-5° high. Leaves ovate 
to ovate-lanceolate, acute or acuminate, entire, den- 
ticulate or remotely dentate, rough above, pubescent 
or glabrous beneath, those of the stem all closely 
sessile, often half-clasping but not connate-perfol- 
iate at the rounded base, 3’-5’ long, 1-2’ wide; 
heads usually numerous, 1-2’ broad; involucre 
nearly hemispheric, its outer bracts ovate or ovate- 
lanceolate, acute, spreading, ciliolate or pubescent; 
rays 15-25; achenes oval or obovate, 4-5” long, 
deeply emarginate. 
On prairies, Ohio to Minnesota, south to Louisiana, 
Nebraska, Arkansas and Texas. Aug.—Sept. 
