234 COMPOSURE. (coMPOSltE FAMILY.) 



- <- Leaves opposite, serrate. Disk-flowers yellow. 



60. Galinsoga. Bays few, short, pistillate, whitish. Involucre of 4-5 thin ovate scales. 



Receptacle chaffy. 



Tribe VI. HELENIOIDE^E. Nearly as Tribe V., but receptacle not chaffy (some- 

 what so in n. 64). In our genera, the disk-flowers perfect and fertile ; the pappus a row 

 of several chaffy scales (bristly-dissected in n. 65) ; the involucre hardly at all imbricated 

 (partly scarious in n. 61). 



# Involucral scales distinct, not glandular-punctate. 



61. Hymenopappus. Rays none. Receptacle flat. Involucre colored. Western. 



62. Actinella. Rays fertile, 3-toothed. Receptacle elevated. Involucre appressed. Western. 

 68. Helenium. Rays fertile or sterile, 3-5-cleft. Receptacle elevated. Involucre small, 



reflexed. Leaves decurrent. 



64. Gaillardia. Ray 3-toothed, or none. Receptacle usually beset with fine fimbrillate 



chaff. Outer involucral scales loose and leafy. Pappus-chaff tipped with the pro- 

 jecting midvein. Western. 



* * Dotted with oil-glands. Involucral scales united into a cup. 



65. Dysodia. Pappus a row of chaffy scales dissected into many bristles. 



Tribe VII. ANTHEMIDE^E. Distinguished from the last two tribes by the more or 

 less dry and scarious imbricated scales of the involucre. Heads radiate (ray mostly 

 white) or discoid, the perfect flowers sometimes sterile and the pistillate rarely tubu- 

 lar. Achenes small ; pappus a short crown or none. Mostly strong- scented , leaves 

 alternate. 



* Receptacle chaffy, at least in part. Heads radiate, many-flowered. 



66. Anthemia. Achenes terete, angled or ribbed. Heads hemispherical, rather large. 



67. Achillea. Achenes obcompressed. Heads small, campanulate or obovate. 



* # Receptacle naked. 

 H- Heads rather large, pedunculate, radiate or rarely rayless. 



68. Matricaria. Receptacle conical. Rays pistillate or none. Pappus crown-like or none. 



69. Chrysanthemum. Receptacle flattish. Rays many, pistillate. Pappus none. 



t- -K Heads mostly small, discoid, corymbed or paniculate. 



70 Tanacetum. Heads corymbed. Achene with broad summit ; pappus a short crown. 



71. Artemisia. Heads in panicled spikes or racemes. Achenes with narrow summit ; 



pappus none. 



Tribe VIII. SENECIONIDE.E. Heads radiate or discoid, the involucre little or 

 not at all imbricated, not scarious. Receptacle naked. Anthers tailless. Pappus 

 capillary. 



* Heads monoecious or subdicecious, the perfect flowers mostly sterile, and the small (ligu- 



late or tubular) ray-flowers in more than one row (at least in the fertile heads). Style* 

 branches obtuse, not appendaged nor hispid. Leaves all radical. 



72. Tussilago. Head solitary, yellow-flowered, monoecious. 



73. Petasites. Heads corymbed, subdioecious. Flowers white or purplish. 



* * Flowers all fertile. Style-branches truncate or capitellate, often appendaged. Involu- 



cral scales connivent-erect. 



- Leaves opposite. 



74. Arnica. Heads showy. Pappus rather rigid, scabrous. 



*- t- Leaves alternate. Pappus soft-capillary, copious. 



75. Senecio. Heads usually radiate. Corollas yellow, 5-toothed. 



76. Cacalia. Heads discoid. Corollas white or cream-colored, 5-cleft. 



77. Erechtiteg. Heads discoid. Flowers whitish, the outer pistillate with filiform corollas. 



