THISTLE FAMILY 257 



Involucral bracts obtuse or merely acute; receptacle naked. 



Leaves bipinnatifld. 3. C. sievioides. 



Leaves simple, spatulate-linear. 4. C. Cusickii. 



Stamens included; some of the outer bracts with spreading tips. 



5. C macrantha. 

 Perennials. 



Leafy-stemmed plants. 



Plant densely white-floccose. 



Leaves mostly basal, broadly obovate in outline, with approximate divergent 

 divisions; branches of the inflorescence usually divergent at the base 

 and curved upwards. 6. C. brachiata. 



Leaves scattered, ovate or lanceolate in outline; branches of the inflorescence 

 ascending or erect, strict. 

 Plant 1-3 dm. high, not fruticulose; leaves regularly pinnatifld. 



7. C. achilleaefnlia. 

 Plant 3-4 dm. liigh. 



Leaves narrow, mostly regularly pinnatifld; plant often fruticulose at 



the base. 8. C. imbricata. 



Leaves broader, interruptedly pinnatifld, with smaller segments inter- 

 posed between the larger ones; plant not fruticulose. 



9. C. cheilanthoides. 

 Plant sparingly floccose, in age greener and glabrate. 



Squameliae about half as long as the corolla; low perennials, 1-2 dm. high, 



branched at the caudex. 10. C humilis 



.Squameliae at least two-thirds as long as the corollas. 



Bracts shorter than the disk; stem 2-4 dm. high; biennial.- with a taproot. 



11. C. Douglasii. 

 Bracts equalling the disk; stems 1-2 dm. high, from a cespitose rootstock. 



12. C. peduncularia. 

 Subscapose perennials, with rosulate leaves and nearly naked peduncles. 



Leaves oblanceolate, elliptic, oi linear in outline; plants with a cespitose caudex. 

 Inner bracts acuminate; leaf-blades narrowly lanceolate in outline. 



13. C. minuscula. 

 Inner bracts merely acute; leaf-blades oblanceolate or oblong in outline. 



14. C. alpina. 

 Leaf-blades obovate-cuneate or flabeUate in outline; plant with a cespitose root- 

 stock. 15. C. Evermannii. 



102. ERIOPHYLLUM Lag. Woolly Yellow Daisy. 

 Leaves entire or merely the earUer ones toothed at the ape.x. 



Achenes glabrous or nearly so. 1. E. pedunculalum. 

 Achenes decidedly pubescent or glandular. 



Leaves narrowly Unear-oblanceolate or Unear. 2. E. gracile. 



Leaves oblanceolate or obovate. 3. E. inlegri folium. 

 Leaves more or less lobed or dissected. 

 Achenes glabrous. 



Bracts acuminate, surpassing the disk. 4. E. multiflorum. 



Bracts abruptly acute, not surpassing the di.sk. .5. E. lanatum. 



Achenes hairy. 6. E. Walsoni. 



103. ANTHEROPEAS Rydb. Daisy Dwarf. 



Pajjpus squameliae all oval or obovate, obtuse; leaves broadly spatulate or obovate; 



ligules yellow or reddish. 1. .4. Wallacei. 



PappiLs squameliae of the angles narrow, linear-lanceolate or linear; leaves linear or 



nearly so; hgules white. 2. A. lanosum. 



104. SYNTRICHOPAPPUS A. Gray. i. S. Fremontii. 



105. TETRANEtJRIS Greene. 



Heads sessile among the leaves. 1. T. depressa. 



Heads distinctly peduncled. 



Stems scapiform, leafy only at the base. 

 Leaves appressed-silky. 



Leaves not strongly 3-nerved on the broadened bases. 



Leaves spatulate or oblanceolate, 2-4 cm. long; scape stout, 5-10 cm. high. 



2. T. septentrionalis. 

 Leaves linear or linear-oblanceolate ; scape 10-20 cm. high. 



Leaves sU very-silky ; hgules 6-8 mm. long. .3. T. acaulis. 



Leaves greenish, sparmgly silky; ligules 8-10 mm. long. 



4. T. simplex. 

 Leaves strongly 3-nerved on the broadened bases, narrowly Unear-oblanceo- 

 late. 5. T. trinervata. 

 Leaves loosely villous or glabrate. 



Leaves, scape, and involucre decidedly villous. 



Involucre more than 1 cm. broad; scape 3-S cm. long: plant densely cespi- 

 tose-pulvinate; leaves not conspicuously broad-based. 



6. T. lanigera. 

 Involucre less than 1 cm. broad; scape 1-3 cm. (rarely 3-5 cm.) long; 



plant loosely cespitose; leaves conspicuously broad-based. 



7. T. brcrifoUa. 



