916 



FLORA. 



Plants not dioecious: flowers all fertile. 



45. Gnaphalium. 



b. Pappus none; leaves broad, alternate, woolly beneath. 46. Adenocaulon 

 * * Heads large; ray-flowers yellow. 47* Inula. 



Tribe 5. Heliantheae. 



A. Disk-flowers perfect, but sterile. 



Achenes thick, short, not flattened; pappus none. 



Achenes merely subtended by the inner involucral bracts. 48. Polymnia. 



Achenes embraced and enclosed by the inner involucral bracts. 



49. Melampodium. 

 Achenes flattened. 



Ray-flowers in 2 or3 series; achenes falling away free. 50. Silphiuvi. 



Ray-flowers in 1 series; achenes adnate to 2 or 3 scales of the receptacle, falling away 

 with them. 



Rays large, yellow. 



Leaves opposite and basal. 51. C/trysogonum. 



Leaves alternate. 



Pappus none, or of 2 caducous awns. 52. Berlatidiera. 



Pappus a persistent irregularly-cleft crown. 53. Engelmannia. 



Rays small, the heads appearing discoid. 54. Parthenium. 



B. Disk-flowers fertile. 

 Ray-flowers persistent upon the achenes. 

 Achenes compressed, or 3-angled; leaves entire. 55. Crassina. 



Achenes short, thick; leaves toothed. 56. Heliopsis. 



Ray-flowers deciduous, or none, 

 f Pappus a cup, or crown, or 0/ a few teeth, azvns, or bristles. 

 1. Achenes, at least those of disk-flowers, not compressed (except in Ratibida and Ver- 



besina) ; scales of the receptacle mostly concave, or clasping. 

 Scales of the receptacle small, awn-like or bristle-like; rays white, short. 



57. Eclipta. 

 Scales of the receptacle broad, larger. 



Involucre of 4 large somewhat united bracts. 

 Involucre of several or numerous separate bracts. 

 Receptacle conic, or columnar. 



Ray-flowers fertile, or wanting; leaves opposite. 

 Ray-flowers sterile, or neutral; leaves mostly alternate. 

 Rays yellow. 



Achenes 4-angled. 60. Rudbeckia. 



Achenes compressed, winged. 61. Ratibida. 



Rays rose-purple. 62. Brauneria. 



Receptacle flat, or convex (low-conic in species of Nos. 64 and 65;. 



Low, fleshy seacoast shrubs. 63. Borrichia. 



Tall herbs, not fleshy. 



Achenes not much flattened, not winged, nor margined. 



64. Helianthus. 

 Achenes of disk-flowers flattened and margined, or winged. 



65. Verbesina. 

 a. Achenes very flat; scales of the receptacle flat, or but slightly concave 



a. Bracts of the involucre all separate. 

 Pappus of 2 short teeth or awns, or a mere border/or none. 66. Coreopsis. 



Pappus of 2-6 awns or teeth, upwardly or downwardly barbed or hispid. 



67. Bid ens. 

 b. Inner bracts of the involucre united to about the middle. 



68. Thelesperma. 



t f Pappus 0/ numerous scales. 

 Leaves opposite, toothed; ray-flowers fertile; rays small. 69. Galinsoga. 



Lea \fs alternate, entire. 



Rays large, neutral ; receptacle deeply honeycombed. 70. 



Rays none; scales of the receptacle narrow, rigid, 71. 



58. Tetragonotheca. 



59. Spilanthes. 



Actitwspermunt. 

 Marshallia. 



