216 COMPOSITyE. (COMPOSITK FAMILY.) 



tacle among the flowers, are called the chaff: when these are wanting, 

 the receptacle is s.iid to he naked. — The largest order of Phfcnoganious 

 plants. It is divided by the corolla into three suborders, only two of 

 which are represented in the Northern United States. The first is much 

 the larger. 



SunonnF.n I. TUBUHFtORiE. 



Corolla tubular in all the perfect flowers, regularly 5- (rarely 3-4-) 

 lobed, ligulate only in the marginal or ray-tlowers, which when present 

 are either pistillate only, or neutral (with neither stamens nor pistil). 



The technical characters of the five tribes of the vast sul)ordcr TubuliJIora, 

 taken from the styles, rc(iuirc a magnifyinj^-glass to make tliem out, and will 

 not always be clear to the student. Tiic following artificial analysis, founded 

 upon other and more obvious distinctions, will be useful to the beginner. (The 

 numbers are those of the genera.) 



Artificial Key to the Genera of this Suborder. 



§ 1. Rays or ligulate flowers none: corollas all tubular (or rarely none). 

 * Flowers of the head all perfect and alike. 

 Pappus composed of bristles ; 



Double, the outer of very short, the inner of longer bristles No. 1 



Simple, the bristleoi all of the same sort. 



Heads few-flowered, themselves aggregated into a compound or dense cluster. . . 2. 

 Heads separate, few-flowered or many-flowered. 



Keceptacle (when the flowers are pulled off) bristly-hairy . . . . 67, 68, "0. 



Kcceptacle deeply honeycomb-like 69. 



Keceptacle uaked. 



Pappus of plumose or bearded stiff bristles. Flowers purple 4. 



Pappus of very plumose bristles. Flowers whitish • . 5. 



Pappus of slender but rather stiff rough bristles 6,7,8,20. 



Pappus of very soft and weak naked bristles 62, 63. 



Pappus composed of scales or cbatf. 



Receptacle naked. Leaves in whorls. 3. 



Iteceptiicle naked. Leaves alternate 45. 



lleceptncle bearing chaff among the flowers. 49. 



Pappus of 2 or few barbed awns or teeth 41,42. 



Pappus none, or a mere crown-like margin to the fruit. 65, 57. 



* * Flowers of two kinds in the .same head. 

 Marginal flowers neutral and sterile, either conspicuous or inconspicuous. . . 65, 66. 

 Marginal flowers pistillate and fertile. 



Keceptacle elongated and bearing broad chaff among the flowers 60. 



Receptacle naked or bearing no conspicuous chalf. 



Pappus of capillary bristles. Involucre imbricated 23, fiS. 59 



Pappus of capillary bristles. Involucre merely one row of scales. . . 14,61. 



Pappus obsolete or none. 



Achenia becoming much loneer than the involucre. 11 



Acheiiia not exceeding the involucre 29, 56, 57. 



♦ » * Flowers of two kinds in .separate heads, the one pistillate, the other staminate. 



Heads dioecious ; in both kinds many-flowered. Pappus capillary 24, 59 



Heads monoecious ; the fertile 1 - 2-flowered and closed. Pappus none. . . . 30, 31 



