226 CARDUACE.\E 



Leaves not spinulose; corolla-tube dilated above. 



15. ISOCOM.\. 



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

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

 hairy: bracts of the involucres broad and abruptly 

 acuminate: appendages of the style-branches ovate to 

 short-subulate. 20. OoxoP.sis. 



Heads radiate. 



Rays scarcely longer than the disk-flower. IS. 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 tliroughout: bracts more or less foliaceous. 



16. Prioxopsis. 

 Pappus persistent. 



Bracts chartaceous, not foliaceous, merely with a green 

 tip: plants annual, or perennial with a caude.x, equally 

 leafy tliroughout: pappus in age more or less spread- 

 ing; achenes turbinate and densely silky. 



17. SiDERANTHTJS. 



Bracts more or less foliaceous, at least above; plants 

 perennial with taproots, large basal leaves, and few 

 and rather small stem-leaves: pappus not spreading; 

 achenes oblong, glabrous or sparingly pubescent. 



18. PYRROCO^LA. 



Leaves entire or toothed, but teeth not spinulose-tipped. 

 Bracts not longitudinally striate. 



Shrubs with glandular-pimctate leaves. 



Heads large, solitary: involucral bracts in about 2 



series; rays numerous. 19. STE.VOTOPSIS. 



Heads small, paniculate or corymbose: bracts well 

 imbricate, in several series; rays few or none. 



1.3. EmrAMERIA. 



Herbs or undershrubs; leaves not glandular-pmictate. 

 Bracts abruptly acuminate: stems leafy up to the 



sessile heads. 20. Ooxopsis. 



Bracts not abruptly acuminate. 



Style-appendages filiform, much longer than the 

 stigmatic portion; low shrubs with wliitish 

 bark and foUaceous outer bracts. 



21. Macroxema. 

 Style-appendages of the stigmas ovate or triangu- 

 lar, not longer than the stigmatic portion. 

 Plants low, cespitose, with a woody caude.\. 

 more or less evergreen leaves, and sohtary 

 peduncled heads. 22. Stexotus. 

 Plants with wholly herbaceous stem, woody, 

 if at all, only at the caudex; leaves not 

 evergreen. 

 Bracts, at least the outer, foliaceous or 

 with foliaceous tips. 

 Disk-flowers tubular ; plants with a tap- 

 root. IS. Pyrrocoma. 

 Disk-flowers more or less widened up- 

 wards; plants with rootstocks or 

 short caudices. 

 Heads sohtary: rays numerous. 



23. Toxestus. 

 Heads corymbiform-cymose ; rays 



small and narrow. 



24. Oriochrysum. 

 Bracts not at all foliaceous or merely with 



green tips. 

 Bracts slightly if at all imequal and 

 shghtly imbricated: heads solitary 

 or few, peduncled. 



45. Erigerox. 

 Bracts well imbricated and unequal in 

 length. 

 Rays not more numerous than the 

 disk-flowers; receptacle alveo- 

 late. 

 Inflorescence racemose or panicu- 

 late; bracts not in vertical 



rows. 25. SOLIDAGO. 

 Inflorescence corymbiform; bracts 

 in distinct vertical rows. 



26. Petrodoria. 

 Rays more numerous than the disk- 

 flowers; receptacle flmbriolate: 

 heads corymbose. 



27. Euthamia. 



