Family ASTERACEA 185 
Tribe 5. HELIANTHE. 
Involucral bracts in 2 to several series, when only 2 series the inner 
and outer of similar texture. 
Ray flowers pistillate, producing seeds. 
Achenes of the ray-flowers winged, imbricated in 2-3 rows; 
disk-flowers perfect but not producing seeds. 1. Silphium. 
Achenes not winged; disk-flowers producing seeds. 
Rays long, yellow. 2. Heliopsis. 
Rays short, nearly white. 3. Verbesina. 
Ray flowers neutral, not producing seeds. 
Rays rose-purple to nearly white, never yellow; achenes not 
compressed or winged. 6. Echinacea. 
Rays yellow or if purple the achenes compressed and winged. 
Achenes neither winged nor much compressed. 
Receptacle conic or convex, pappus of very small teeth or 
none. 4. Rudbeckia. 
Receptacle flat, conic or convex, pappus of 2 large scales or 
awns, sometimes with 2-4 smaller ones. 7. Helianthus. 
Achenes compressed and winged. 
Receptacle columnar to subulate; leaves divided or parted. 
5. Ratibida. 
Receptacle convex or conic; leaves serrate, decurrent on the 
stem. 7 8. Ridan. 
Involucral bracts imbricated in 2 series, the inner membranous, very 
different from the outer in texture; rays yellow or none. 
Inner bracts distinct or slightly united at the base; rays some- 
times lacking. 
Pappus of 2-5 downwardly barbed awns or teeth, outer bracts 
often as long or longer than the inner; rays often lacking. 
10. Bidens. 
Pappus not downwardly barbed, the outer bracts very small. 
9. Coreopsis. 
Inner bracts united to about the middle, the outer much smaller. 
11. Thelesperma. 
1. Silphium. 980. 
Leaves opposite or the upper alternate. 
Stems square; leaves perfoliate. 1. S. perfoliatum. 
Stems round; leaves not perfoliate. 2. S. integrifolium. 
Leaves all alternate, the basal pinnatifid. 3. S. laciniatum. 
1. Silphium perfoliatum L. Cup-plant. 
In wet soil in the eastern part of the state. Indianola; Lincoln; 
Nebraska City; Turner; Wahoo; Walton; Wymore; Weeping Water. 
2. Silphium integrifolium Michx. Rosin-weed. 
Common in prairies in the eastern part of the state. Franklin; Lin- 
coln: Nebraska City; Newark; Plainview; Red Cloud; Wahoo; Weep- 
ing Water; Wymore. 
3. Silphium laciniatum L. Compass-plant. 
Common in low prairies in the eastern part of the state. Foster; 
Fremont; Lincoln; Nebraska City; Weigand; Wymore; Weeping 
Water. 
2. Heliopsis. 984. 
te Heliopsis scabra Dunal. Ox-eye. 
Common in the eastern part of the state. Arapahoe; Callaway; 
