THISTLE FAMILY 257 



Involucral bracts obtuse or merely acute; receptacle naked. 



Leaves bipinnatifld. 3. C. stevioides. 



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



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



5. C. macrantha. 

 Perennials. 



Leafy-stemmed plants. 



Plant densely whlte-floccose. 



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

 divisions; branches of the inflorescence usually divergent at the base 

 and curved upwards. 6. C. brachtttta. 



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

 ascending or erect, strict. 

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



7. C. acMUeaefnlia. 

 Plant 3-4 dm. high. 



Leaves narrow, mostly regularly pumatifld; plant often frUticulose at 



the base. 8. C. imbricaia. 



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. 



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



branched at the caudex. 10. C. humilis 



Squamellae 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 e.qualling the disk; stems 1-2 dm. high, from a cespitnse rootstock. 



12. C. peduncularitt. 

 Subscapose perennials, with rosulate leaves and nearly naked peduncles. 



Leaves oblanceolate, elUptic, oi Unear 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 outUne. 



14. C. alpina. 

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

 stock. 15. C. Evermannii. 



102. ERIOPHYLLUM Lag. Woolly Yellow Daisy. 



Leaves entire or merely the earlier ones toothed at the apex. 



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



Achenes decidedly pubescent or glandular. 



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



Leaves oblanceolate or obovate. 3. E. integrifolium. 



Leaves more or less lobed or dissected. 

 Achenes glabrous. 



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



Bracts abruptly acute, not surpassing the disk. fi. E. lanatum. 



Achenes hairy. 6. E, Waisoni. 



103. ANTHEROPEAS Rydb. Daisy Dwarf, 



Pappus squamellae all oval or obovate, obtuse; leaves broadly spatulate or obovate; 



Iigules yellow or reddish. 1. A. WaUacei. 



Pappus squamellae of the angles narrow, linear-lanceolate or linear; leaves linear or 



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



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



105. TETRANEURIS Greene. 



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



Heads distuietly 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 em. long; scape stout, 5-10 cm. high. 



2. T. septentrionalis. 

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



Leaves silvery-silky; Ugules 6-8 mm. long. 3. T. acaulis.- 



Leaves greenish, sparingly silky; Ugules 8-10 mm. long. • 



4. T. simplex. 

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

 late. 5. T. trinervata. 

 Leaves loosely viUous or glabrate. 



Leaves, scape, and involucre decidedly villous. 



Involucre more than 1 cm. broad; scape 3-8 cm. long; plant densely cespi- 

 tose-pulvlnate; 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. brevifolia. 



