COMPOSITAE. Vor. III. 
6. Silphium terebinthinaceum Jacq. 
Prairie Dock. Prairie Burdock. 
Fig. 4426. 
Silphium terebinthinaceum Jacq. Hort. Vind. 
ri pl, 43. EPPO, 
S. pinnatifidum Ell. Bot. S. C. & Ga. 2: 462. 
1824. : 
Silphium terebinthinaceum pinnatifidum A. 
Gray, Man. 220. 1848. 
Stem glabrous or nearly so, branched 
and scaly above, 4°-10° high. Leaves all 
basal or nearly so, coriaceous, ovate, mostly 
long-petioled, acute at the apex, cordate 
at the base, rough on both sides, often 12’ 
long and 6’ wide, sharply dentate, laciniate 
or pinnatifid; heads numerous, 14-3’ broad, 
borne on glabrous peduncles; involucre 
hemispheric, its bracts ovate-oblong, erect, 
glabrous or minutely pubescent; rays 12-20; 
achenes obovate, narrowly winged, slightly 
2-toothed and emarginate at the apex. 
On prairies and in dry woods, southern On- 
tario and Ohio to Minnesota, south to Georgia, 
Iowa and Louisiana. Rosin-plant. July-Sept. 
7. Silphium reniforme Raf. Kidney- 
leaved Silphium. Fig. 4427. 
Silphium. reniforme Raf.; Nutt. Trans. Am. 
Phil. Soc. (II) 7: 342. 1840. 
S. compositum reniforme T. & G. Fl. N. A. 2: 
276. 1842. 
Stem scape-like, 3°-6° tall, glabrous or 
nearly so, corymbosely branched above. 
Leaves mostly basal, broadly ovate to reni- 
form, 4’-15’ long, obtuse or abruptly point- 
ed, coarsely dentate, deeply cordate at the 
base, long-petioled; heads numerous, about 
1’ broad, the peduncles glabrous; involucre 
campanulate, the bracts ovate or broadly 
oblong to narrowly oblong or oblong-spatu- 
late, obtuse; rays several, yellow; achenes 
suborbicular or orbicular-obovate, 34” long, 
the wings prolonged enough to form a shal- 
low apical sinus. 
In dry or stony soil, mountains of Virginia 
and North Carolina. July—Aug. 
Silphium compositum Michx., a_ related 
southern species with pedately parted leaves, 
is reported as observed in southern Virginia. 
52. CHRYSOGONUM L. Sp. Pl. 920. 1753. 
Pubescent perennial herbs, with opposite and basal petioled leaves, and slender-peduncled- 
axillary and terminal, rather large heads of both tubular and radiate, yellow flowers. Invo- 
lucre hemispheric, its bracts in 2 series of 5, the outer large, obovate or spatulate, foliaceous, 
the inner oval, firm, each subtending a pistillate ray-flower. Receptacle chaffy, each scale 
subtending and partly enclosing a perfect but sterile tubular Mower with a 5-toothed corolla. 
Anthers nearly entire at the base. Achenes obovate, compressed, their margins acute, not 
winged, 1-nerved on the back, 1-2-ribbed on the inner side. Pappus a short half-cup-shaped 
crown. [Greek, golden-knee.] 
A monotypic genus of eastern North America. 
