THISTLE FAMILY 835 



Heads small, paniciilate or corymbose; bracts well 

 imbricate, in several series; rays few or none. 



13. Ericameria. 

 Herbs or undershnibs ; leaves not glandular-pxmctate. 

 Bracts abruptly acuminate; stems leafy up to the 



sessile heads. 20. OONOPSIS. 



Bracts not abruptly acuminate. 



Style-appendages filiform, much longer than the 

 stigmatic portion; low shrubs with whitish 

 bark and foliaceous outer bracts. 



21. Macronema. 

 Style-appendages of the stigmas ovate or triangu- 

 lar, not longer than the stigmatic portion. 

 Plants low, cespitose, with a woody caudex, 

 more or less evergreen leaves, and solitary 

 pedimcled heads. 22. Stenottjs. 

 Plants with wholly herbaceous stem, woody, 

 if at all, only at the caudex; leaves not 

 evergreen. 

 Bracts, at least the outer, foUaceous or 

 with foUaceous tips. 

 Disk-flowers tubular ; plants with a tap- 

 root. 18. PYRROC'OMA. 



Disk-flowers more or less widened up- 

 wards; plants with rootstocks or 

 short caudices. 

 Heads soUtary; rays numerous. 



23. TONESTUS. 



Heads corymbiform-cymose; rays 

 small and narrow. 



24. Oriochrtsum. 

 Bracts not at all foUaceous or merely with 



green tips. 

 Bracts slightly if at aU imequal and 

 sUghtly imbricated; heads soUtary 

 or few, peduncled. 



45. Erigeron. 

 Bracts well imbricated and unequal in 



length. 

 Rays not more nximerous 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 fimbriolate ; 

 heads corymbose. 



27. EUTHAMLA.. 



Bracts of the involucres longitudinaUy striate; heads in con- 

 gested corj-mbs. 28. Oligoneuron. 

 Ray-flowers blue, pink, or white. 



1 . Pappus a mere crown or of few scales or awn-Uke bristles. 



Pappus of a cup-shaped crown and a single awn ; dwarf annuals, branched 

 at the base. 29. Monoptilon. 



Pappus of a series of long awns or that of the rays of short scales; annuals 

 or perennials. 30. To\vnsendia. 



2. Pappus of nmnerous capillary bristles. 



a. Rays only sUghtly if at aU exceeding the pappus; annuals. 

 Bracts in 2-3 series, the outer foUaceous; stigma-tips acute. 



31. Brachyactis. 

 Bracts in 1-2 series, narrow, not foUaceous; stigma-tips obtuse. 



46. Leptilon. 



6. Rays conspicuous, longer than the pappiis, iisually equalUng or exceed- 

 ing the width of the disk. 

 Style-tips lanceolate or oblong to filiform. 



Bracts in a single series, with hyaline-scarious erose-flmbriate mar- 

 gins ; dwarf winter annuals. 32. Eremiastrum. 

 Bracts in at least 2 or usuaUy in more than 2 series. 

 Pappus simple, of similar bristles. 



Plants rtish-Ulce, spiny. 33. Leucosyris. 



Plants not spiny. 



Perennials, with a rootstock or caudex. 



Bracts acuminate, as well as the leaves tipped with 

 callous points or spines; plants with soUtary 

 heads at the ends of the stems or branches, and 

 cespitose caudices. 



