642 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
Achenes with retrorsely barbed awns; rays sterile or fertile. 
Rays sterile; all achenes awned...........---- 66. BrpEens (p. 703). 
Rays fertile; outer achenes usually not awned. 
67. HeTEROsPERMUM (p. 705). 
Achenes, at least those of the disk, never obcompressed; involuere various. 
Rays white; stems prostrate, spreading; bracts of receptacle reduced to 
awnlike bristles subtending the naked achenes. 
68. Ecripra (p. 705). 
Rays yellow or brown; stems erect; bracts of receptacle concave, loosely 
subtending the disk achenes. 
Receptacle conic or columnar. 
Achenes flattened, distinctly margined or winged. 
69. Ratrerpa (p. 705). 
Achenes not, flattened, terete or 4-angled, not margined nor winged. 
Achenes terete or nearly so; leaves somewhat glaucous. 
70. Dracorts (p. 706). 
Achenes 4-angled; leaves never glaucous. 
Achenes quadrangular-compressed, the apex covered by the base 
of the corolla tube..........-.---- 2. GYMNOLOMIA (p. 707). 
Achenes nearly equally 4-angled, the apex not covered by the 
base of the corolla......-....-.-.-.-- 71. RupBecktia (p. 707). 
Receptacle from flat to convex. 
Achenes of the disk not winged nor very flat, when flat not “margined 
nor sharp-edged; pappus sometimes dec iduous, or often wanting. 
Rays fertile. 
Pappus of conspicuous awns; leaves not 3-lobed. 
74. WyerTntia (p. 709). 
Pappus none in the disk achenes; leaves 3-lobed. 
73. ZALUZANIA (p. 708). 
Rays sterile (rarely wanting), 
Pappus none or a minute ring.......... 72. GyMNoLomra (p. 707). 
Pappus of 2 awns or palez. 
Achenes pubescent; pappus persistent or deciduous. 
75. VIGUIERA (p. 709). 
Achenes glabrous; pappus deciduous. .76. HeLniantius (p. 710). 
Achenes of the disk winged, or flat-compressed and margined, or thin- 
edged; pappus persistent. 
Shrub; rays wanting..................0..- 77. FLourenstia (p. 711). 
Herbs; rays present. 
Achenes not winged nor margined. 
Leaves linear; pappus of 2 palese without intermediate squamel- 
78. ENCELIA (p. 712). 
Leaves not linear; palesee with intermediate squamelle. 
79. HELIANTHELLA (p. 712). 
Achenes winged or margined. 
Only the ray flowers fertile; perennial. 
81. WooToNELLA (p. 713). 
All the flowers fertile; annuals or perennials, 
Annual; involucral bracts foliaceous, spreading. 
80. NIMENESIA (p. 713). 
Perennials; bracts usually not foliaceous, all, or all except the 
outermost, appressed............ 82. VERBESINA (p. 713). 
