WOOTOISr AND STANDLEY PLOEA OF NEW MEXICO. 641 



Tribe V. HELIANTHEAE, 



Involucral bracts (uniserial) partly or wholly inclosing the achcnes of the ray flowers; 

 pappus none in the ray achenes. 

 Rays inconspicuous, scarcely exserted; plants viscid; achenes laterally com- 

 pressed 51. Madia (p. 697). 



Rays showy; plants not viscid; achenes not laterally compressed. 



52. Blepharipappus (p. 698). 

 Involucral bracts not inclosing the ray achenes; pappus various. 

 Disk flowers sterile. 



Involucres cylindric or fusiform, few-flowered. 

 Leaves, at least some of them, connate, simple; achenes oblong, without diver- 

 gent awns or horns 53. Guardiola (p. 698). 



Leaves never connate, dissected into linear-filiform segments; most of the 

 achenes bearing a pair of divergent awns or horns. 



54. DiCRANOCARPUS (p. 698). 

 Involucres campanulate or hemispheric, many-flowered. 

 Rays white. 



Rays long and showy; leaves entire 55. Melampodium (p. 698). 



Rays scarcely if at all exceeding the disk; leaves lobed or pinnatifid. 



56. Parthenium (p. 699). 

 Rays yellow. 

 Achenes strongly flattened, unicostate on the inner face; pappus nearly 

 obsolete or else -evanescent; plants finely canescent. 



57. Berlandiera (p. 699). 

 Achenes carinate on both surfaces; i>appus conspicuous, persistent; plants 



rough-hirsute 5S. Engelmannia (p. 700). 



Disk flowers fertile. 

 Rays persistent on the achenes and becoming papery. 

 Annuals; rays short and inconspicuous, greenish white; leaves petiolate, en- 



the 59. Sanvitalia (p. 700). 



Perennials; rays showy, white or yellow; leaves mostly sessile, sometimes 

 toothed. 

 Disk achenes compressed; leaves entii'e; plants low, less than 20 cm. high. 



60. Crassina (p. 700). 

 Disk achenes obtusely 4-angled; leaves toothed; plants tall, usually 50 cm. 



high or more 61. Heliopsis (p. 701). 



Rays deciduou?, thin, or wanting. 

 Pappus of several to many hyaline palese (rarely wanting). 



Rays wliite; heads very small; leaves opposite 62. Galinsoga (p. 701). 



Rays yellow or brown; heads large; leaves alternate. 



97. Gaillardia (p. 719). 

 Pappus various but never of conspicuous hyaline scales. 

 Achenes obcompressed; involucre of 2 distinct series. 

 Rays pink; achenes slender, beaked; slender annual. 



63. Cosmos (p. 701). 

 Rays yellow, rarely wanting; achenes various; annuals or perennials. 

 Bracts of imier involucre united at least to the middle. 



64. Thelesperma (p. 702). 

 Bracts distinct or nearly so. 

 Achenes not awned; pappus obscure or wanting; rays neutral. 



65. Coreopsis (p. 703). 

 52576°— 15 41 



