THISTLE FAMILY 835 



Heads small, paniculate or corymbose; bracts well 

 imbricate, in several series; rays few or none, 

 i:?. Ekkamkhia. 

 Herbs or undcrshriibs ; leaves not glandular-pmictate. 

 Bracts abruptly acuminate; stems leafy up to the 



sessile heads. 20. OONOP.sis. 



Bracts not abruptly acuminate. 



Style-appendages filiform, much longer than the 

 stigmatic portion; low shrubs with whitish 

 bark and foliaceous outer bracts. 



21. Macroneal\. 

 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 

 peduncled heads. 22. Stenotus. 

 Plants with wholly herbaceous stem, woody, 

 if at all, only at the caudex; leaves not 

 evergreen. 

 Bracts, at least the outer, foliaceous or 

 with foUaceous tips. 

 Disk-flowers tubular ; plants with a tap- 

 root. 18. Ptrrocoma. 

 Disk-flowers more or less widened up- 

 wards; plants with rootstocks or 

 short caudices. 

 Heads solitary; rays numerous. 



2.3. TONESTU.S. 



Heads corymbiform-cymose ; rays 

 small and narrow. 



24. Oriochrysttm. 

 Bracts not at all foUaceous or merely with 

 green tips. 

 Bracts slightly if at all imequal and 

 sUghtly imbricated; heads solitary 

 or few, peduncled. 



4.5. 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 tlian the disk- 

 flowers; receptacle flmbriolate; 

 heads corvmbose. 



27. EUTHAML\. 



Bracts of the involucres longitudinally striate; heads in con- 

 gested corj-mbs. 28. Oligoneltron. 

 b. Ray-flowers blue, pink, or white. 



J . Pappus a mere crown or of few scales or awn-like bristles. 



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



at the base. 20. IMoxoptilon. 



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

 or perennials. 30. TOWXSEXDIA. 



2. Pappus of numeroiLS capillary bristl&s. 



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

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



31. Braciiyactis. 

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



46. Leptilon. 



b. Rays conspicuous, longer than the pappus, usually equalling or exceed- 



ing the width of the disk. 

 Style-tips lanceolate or oblong to fiUform. 



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

 gins ; dwarf winter aimuals. 32. Ereml\strum. 

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

 Papiius siniple, of similar bristles. 



Plants rush-like, spiny. 33. Leucosyris. 



Plants not spiny. 



Perennials, with a rootstock or caudex. 



Bracts acuminate, as weU as the leaves tipped with 

 caUous points or spines; plants with solitary 

 heads at the ends of the stems or branches, and 

 cespitose caudices. 



