Flora of the Palouse Region 201 



above, woolly beneath, but soon green and glabrate on both sides, 5-20 cm. 

 long: prickles rather weak: heads large, usually clustered, short-peduncled, 

 often surrounded by the upper leaves: involucre persistently white-woolly; 

 bracts loose, all tapering to slender rather weak prickly points, the outer 

 broader and shorter, not glandular: corolla purple, the lobes thickened at 

 the tips, shorter than the throat: pappus-bristles a little thickened at the 

 tips. Moist places, Thatuna Hills, rare. 



C. lanceolatum vScop. Stems stout, somewhat woolly, usually branched, 

 leafy to the top, 1-1.5 m. high: leaves lanceolate, deeply pinnatifid, hispid- 

 pubescent but green above, white-tomentose beneath, decurrent at base, 

 6-15 cm. long, armed with numerous stout prickles: heads large, on stout 

 leafy peduncles: involucre well imbricated, sparsely woolly: bracts lanceo- 

 late, acuminate, all tipped with stout erect spiny points: flowers purple. 

 Abundantly introduced. 



337. CENTAUREA. 



Herbs: heads many-flowered: flowers all with tubular and deeply 

 5-cleft corollas, some of the marginal ones commonly sterile, these 

 not enlarged nor conspicuous, the others perfect and fertile: invol- 

 ucre globular, the scales tipped or margined with spines or scar- 

 ious appendages: receptacle very bristly: pappus of numerous 

 rigid or sometimes chaffy naked bristles: akenes mostly com- 

 pressed, attached by one margin just above the base. 



C. nigra L. Perennial, 30-60 cm. high, rough-pubescent: lower leaves 

 oblong or spatulate, entire or dentate, petioled; upper lanceolate, sessile, 

 mostly entire, acute: heads 2 cm. broad; bracts dark-brown, pectinately 

 fringed, the uppermost scarious, margined, erose: flowers red, all perfect, the 

 marginal ones not enlarged: akenes 4-sided: pappus none. Sparingly intro- 

 duced. 



