286 COMPOSITE, (composite family.) 



The technical characters of the tribes, taken from the styles, require a mag- 

 nifyiug-glass to make them out, and will not ahvays be clear to the student. 

 The following artificial analysis, founded upon other and more obvious dis- 

 tinctions, Avill be useful to the beginner. 



Artificial Key to the Genera of the Tubuliflorae. 



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

 * 1. Flowers of the head all perfect and alike. 

 Pappus composed of bristles : 



Double, the outer of very short, tlie inner of longer bristles No. 2 



Simple, the bristles all of the same sort. 

 Heads few -flowered, themselves aggregated into a compound or dense cluster . . 1 

 Heads separate, few-flowered or many-flowered. 

 Receptacle (when tlie flowers are pulled off) bristly-hairy .... 78,70,80 



Receptacle deejjly honeycomb-like 81 



Receptacle naked. 

 Pappusof plumose or bearded stiff bristles. Flowers purple .... 8 



Pappus of verj- plumose bristles. Flowers whitish 6 



Pappus of slender but rather stiff" rough bristles . . . . 4,5,7,9,16 



Pappus of verj- soft and weak naked bristles 76, 77 



Pappus comj)Osed of scales or chaff. 



Receptacle naked. Leaves in whorls 3 



Receptacle naked. Leaves alternate, dissected 61 



Recejitacle bearing chaff among the flowers 59, 64 



Pappus of 2 or few awns or teeth 12, 53, 57, barbed in 55, 56 



Pappus none, or a mere crown-like margin to the fruit 36, 68, 71 



« 2. Flow'ers of two kinds in the same head. 

 Marginal flowers neutral and sterile, either conspicuous or inconspicuous ... 82 

 Marginal flewers pistillate and fertile. 

 Receptacle elongated and bearing broad chaff among the flowers . . . .29,30 



Receptacle convex, chaffy. Achene flat, 2-awned 52 



Receptacle naked or bearing no conspicuous chaff. 



Pappus of capillary bristles. Involucre imbricated 28, 32, S3 



Pappus of capillary bristles. Involucre merely one row of scales . . .26, 73, 77 

 Pappus a short crown or none. 



Achenes becoming much longer than the involucre 34 



Achenes not exceeding the involucre '42, 70, 71 



* 3. Flowers of two kinds in separate heads, the one pistillate, the other stamiuate. 



Heads dioecious : in both kinds many-flowered. Pappus capillary . . 27, 31, 82, 79 



Heads monoecious; the fertile 1-2-flowered and closed. Pappus none . . . 43,44 



§ 2. Rays jiresent ; i. e. the marginal flowers or some of them with ligulate corollas. 



« 1. Pappus of capillary bristles, at least in the disk. (Rays all pistillate. ) 



Rays occupying several rows 26, 72, 73 



Rays in one marginal row, and 



White, purple or blue, never yellow 17, 24, 25, 26, 73 



Yellow, of the same color as the disk. 

 Pappus (at least in the disk) double, the outer short and minute . . .13, 14 

 Pappus simple. 

 Scales of the involucre equal and all in one row. Leaves alternate . . .75 



Scales of the involucre in two rows. Leaves opposite 74 



Scales of the involucre imbricated. Leaves alternate . . . 10,11,15,17,35 

 * 2, Pappus a circle of awns or rigid bristles (at least in the disk), 



Ray yellow, awns few (2-8) 12 



Ray roee-color 23 



