Jones: Flora of Illinois, 152. Compositae 245 



39. Bracts acute or acuminate; ray-flowers neutral, deciduous.... 



.29. Helianlbus 



37. Achenes flattened. 



40. Rays numerous; bracts thick, in several rows; coarse herbs with 



resinous sap; disk flowers perfect but sterile 21. Silphium 



40. Rays mostly 8; bracts in two series; disk flowers fertile 



32. Coreopsis 



36. Leaves alternate or basal. 



41. Leaves or some of them deeply lobed or divided; stem not winged. 

 42. Receptacle conical to columnar. 



43. Achenes flattened, broad-margined or winged 27. Ralibida 



43. Achenes 4-sided, not at all margined or winged 



25. Rudhec}(ia 



42. Receptacle flat or convex ; achenes flattened, 2-winged, notched 



at the apex 2l. Silphium 



41. Leaves serrate or entire. 



44. Stems scapose; leaves all basal, spatulate, entire 36. Aclinea 



44. Stems leafy. 



45. Stems more or less winged by the decurrent bases of the 

 leaves (except Helenium tenuifolium). 

 46. Rays 3-lobed, 10-18; pappus of 5-8 acuminate or aristate 



scales 37. Helenium 



46. Rays entire or emarginate; pappus of 1-3 subulate awns. 



47. Heads several to many, corymbose; rays 2-8 



30. Actinomeris 



47. Heads solitary or few; rays 8-15 31. Verbesina 



45. Stems not winged. 



48. Receptacle conical; pappus a mere crown, or none; disk 



flowers purple 25. Rudbeclfia 



48. Receptacle flat or convex; pappus of 2 deciduous, trans- 

 lucent scales or awns; disk flowers yellow or brownish 

 29. Helianihus 



32. Rays not yellow. 



49. Leaves opposite; ray-flowers small, white. 



50. Leaves angulate-lobed, thin, dilated at the base; plants glandular- 

 pubescent; corolla-tube of the ray-flowers pubescent 20. Pol^mnia 



50. Leaves serrate. 



51. Leaves ovate, petioled 28. Calinsoga 



51. Leaves lanceolate, sessile 24. Eclipta 



49. Leaves alternate. 



52. Leaves dissected or incised; bracts scarious. 



53. Rays 4-6, short; heads numerous 39. Achillea 



53. Rays 10-30; heads fewer. 



54. Leaves cut into filiform divisions; receptacle chaffy 



40. Anihemis 



54. Leaves incised or coarsely and irregularly toothed 



42. Chrysanthemum 



52. Leaves entire to serrate or dentate. 



55. Receptacle conical or columnar; rays purple, reflexed 



26. Echinacea 



55. Receptacle fiat or convex; rays spreading, white or pink. 



56. Leaves entire, lanceolate; rays many, lilac or white... 13. 5o//onia 

 56. Leaves ovate, dentate; rays 5, white, short 22. Parthenium 



31. Heads rayless. 



57. Flowers green or greenish. 



58. Staminate and pistillate flowers in the same head, or flowers all perfect. 

 59. Heads few or solitary; receptacle conical; bracts short, oval, obtuse, 

 scarious; leaves finely dissected, with pineapple odor when crushed.... 

 41. Matricaria 



