834 CARDUACEAE 



Tribe 3. ASTEREAE. 



A. Plants not dioecious. 



I. Marginal pistillate flowers, if present, ligulate. 

 a. Ray-flowers yellow or none. 



1. Pappus of scales or awns or lacking, never of numerous capillary bristles. 

 a. Bracts not conspicuously s carious-margined . 



Heads small, not over 4 mm. high, few-flowered; pappus more or less 



aleaceous. 

 Disk-flowers usually fertile; leaves linear to flUform. 



7. GUTIERREZIA. 



Disk-flowers sterile; leaves short, obovate or spatulate. 



8. AiMPHIPAPPUS. 



Heads large, many-flowered; involucre in all except one species viscid. 

 Involucres hemispherical ; pappus of a few deciduous a-vvns. 



9. Geindelia. 

 Involucres turbinate; pappus of persistent linear, very acute paleae. 



10. Vanclevea. 

 6. Bracts with conspicuous scarious fimbriate margins. 



1 1 ACAMPTOPAPPTTS. 



2. Pappus at least in part of ntmaerous capillary bristles. 

 a. Pappus double, the inner of capillary bristles, the outer of paleae or 



short bristles; involucres many-flowered, hemispherical with narrow 

 imbricated bracts. 12. Chrysopsis. 



0, Pappus wholly of capillary bristles. 

 Heads discoid. 



Leaves resinous-punctate. 13. Ericameria. 



Leaves not resinous-punctate. 



Involucres narrowly tm-binate. its bracts more or less charta- 

 ceous, keeled, arranged in definite (usually 5) vertical ranks; 

 achenes elongate-linear; tips of style-branches subulate-fili- 

 form. 14. Chrysothamnxjs. 



Involucres broadly turbinate to hemispheric, its bracts more or 



less imbricate, but not in definite vertical ranks ; achenes 

 scarcely elongate-hnear. 

 Style-tips obtuse; involucral bracts narrow and poorly im- 

 bricate. (Rayless species of) 45. Erigeron. 

 Style-tips acute; bracts either broad or well imbricate or 



both. 



Achenes truncate at the top, gradually tapering towards 



the base, iisually cinereous-pubescent ; bracts neither 

 broad nor abruptly acuminate. 

 Appendages or tips of the style-branches filiform; 

 undershrubs with white-tomentulose stems and 

 glandular-hairy foliage; leaves entire-margined. 



21. MACRONEMA. 



Appendages or tips of the style-branches subulate to 



ovate. 

 Leaves with spinulose-tipped teeth; corolla-tube 

 slender. (Rayless species of) 



17. Stderanthtjs. 

 Leaves not spinulose; corolla-tube dilated above. 



15. ISCKOMA. 



Achenes elongate-obovoid, i, e., tapering at both ends, 

 but more so below, multi-striate, glabrous or slightly 

 hairy; bracts of the uivolucres broad and abruptly 

 acuminate ; appendages of the style- branches ovate to 

 short-subulate. 20. Oonopsis. 



Heads radiate. 



Rays scarcely longer than the disk-flower. 18. Pyrrocoma. 

 Rays conspicuous, much exceeding the disk. 



Leaves pinnate or toothed; lobes or teeth spinulose-tipped. 

 Pappus of the fertile achenes deciduous in a ring; annuals, 

 equally leafy throughout; bracts more or less foUaceous. 



16. Prioxopsis. 

 Pappus persistent. 



Bracts chartaceous, not foliaceous, merely with a green 

 tip; plants annual, or perennial with a caudex, equally 

 leafy throughout; pappus in age more or less spread- 

 ing; achenes turbinate and densely silky. 



_ 17. Sideranthus. 



Bracts more or less foliaceous. at least above; plants 

 perennial mth taproots, large basal leaves, and few 

 and rather smail stem-leaves; pappus not spreading; 

 achenes oblong, glabrous or sparingly pubescent. 



18. Pyrrocoma. 



Leaves entn-e or toothed, but teeth not spinulose-tipped. 

 Bracts not longitudinally striate. 



Shrubs with glandular-punctate leaves. 



Heads large, soUtary; involucral bracts in about 2 

 series ; rays numerous. 19. Stexotopsis. 



