COMPOSITAE 465 



kinds of flowers it is called heterogamous and when only one kind, homo- 

 gamous. 



1. Flowers all tubular or campanulate, no ray-flowers present. 

 2. Flowers homogaihous, that is, all perfect and alike. 

 3. Heads few to many, many-flowered, not crowded in dense involucrate 

 masses or spicately arranged. 

 4. Involucral-bracts in several series. 

 5. Pappus of long hairs. 



6. Style-arms, slender, hairy...^. 1. Vemonia 



6. Style-arms glabrous or nearly so 2. Eupatoriwm 



5. Pappus of 5 awned scales 3. Ageratum 



4. Involucral bracts in a single series 4. Emilia 



3. Heads few-flowered, fascicled, forming dense, often subcapitate and 

 involucrate. clusters, or in pairs and spicately arranged. 



5. Elephantopus 



2. Flowers heterogamous, the outer ones female, the inner ones perfect. 



3. Heads arranged in dense, globose, peduncled masses; branches 



■winged 6. Sphaeranthus 



3. Heads not arranged in globose masses, corymbose, panicled, or 

 racemose. 

 4. Pappus of numerous soft hairs. 



5. Herbs, often coarse and shrub-like; involucral scales narrow; 



.flowers usually yellow 7. Blumea 



5. Low shrubs with slender stems and pale-purple flowers; in- 

 volucral bracts broad ; 8. Pluehea 



4. Pappus none, cup-like, or of scales or spines, not hairy. 

 5. Pappus represented by a bristly or toothed, cup-like ring. 



9. Grangea 

 5. Pappus of small lacerate or divided scales .... 10. Crossostephium 

 5. Pappus of spines terminating the angles, 2 to 3 times as long 



as the achenes : 11. Synedrella 



5. Pappus none. 

 6. Rather coarse aromatic herbs with numerous heads. 



12. Artemisia 

 6. Slender, prostrate or spreading, very small herbs with solitary 

 heads. 



7. Heads short-peduncled; anther-cells tailed 13. Epaltes 



7. Heads sessile; anther-cells not tailed. 14. Centipeda 



1, Ray-flowers present, 1 or more outer rows ligulate, the disk-flowers 

 tubular. 



2. Pappus of few to many hairs 15. Erigeron 



2. Pappus of awns or scales, or none. 

 3. Pappus cupular, scale-like, or none. 

 4. Involucral-bracts unite'd; rank scented cultivated herbs with large 



yellow flowers 16- Tagetes 



4. Involucral-bracts free or nearly so. 

 5. Receptacle smooth or pitted, not paleaceous.. 17. Chrysanthemum 

 5. Receptacle paleaceous. 

 6. Outer 4 bracts large, foliaceous, in opposite pairs. 



18. Enhydra 

 6. Bracts all similar, or at least the outer 4 not foliaceous. 



111666 80 



