COMPOSITAE. 251 



Stems many-leaved; involucre imbricated. H. canadense. 



Stems few-leaved; involucre a series of equal bracts and a 



few short outer ones. 



Flowers white; involucre nearly glabrous. H. albiflorum. 



Flowers yellow; involucre hairy or glandular. 



Heads small, black-hairy. " H. gracile. 



Heads larger; hairs not black. H. scouleri* 



Hieracium canadense Michx. Somewhat scabrous throughout; stems 

 stout, 30-120 cm. high; leaves numerous, lanceolate, entire or incisely serrate, 

 sessile and somewhat clasping at base, gradually smaller upwards, 1-10 cm. 

 long, none clustered at base; heads corymbed, rarely solitary, on stout pe- 

 duncles; involucre hemispheric, puberulent or glabrous, sometimes glandular, 

 1-2 cm. broad, the bracts in 2-3 series, the uppermost loose; akenes columnar; 

 pappus brownish. Low ground, rare. 



Hieracium canadense columbianum (Rydb.) Piper. (H. columbianum 

 Rydb.) Lower part of stem pilose, otherwise as in the species. Spokane 

 County. 



Hieracium albiflorum Hook. Stems slender, erect, 50-80 cm. high, villous 

 below; leaves oblong or oblong-spatulate, thin, entire or faintly toothed, the 

 lower tapering into broad petioles, the upper mostly sessile, all beset with 

 sparse villous white hairs, especially the lowest; heads 15-30-flowered; in- 

 volucre narrow, glabrous or with a few hairs, the bracts linear-lanceolate, pale; 

 akenes strongly striate. In dry open woods. 



Hieracium gracile Hook. Tufted; stems usually several, 15-30 cm. high; 

 leaves mostly basal, oblong-spatulate, entire or nearly so, broadly petiolate, 

 3-8 cm. long, glabrous or merely puberulent; heads several, racemose or corym- 

 bose; involucre 8 mm. high, blackish with both hirsute and glandular hairs; 

 akenes cylindric; pappus sordid or fuscous. An alpine species occurring on 

 the higher peaks of the Blue Mountains. 



Hieracium scouleri Hook. Erect, 30-60 cm. high, densely beset throughout 

 with long soft white hairs with swollen bases; basal leaves lanceolate or ob- 

 lanceolate, entire, acute or obtuse, 10-20 cm. long, tapering into margined 

 petioles; cauline similar, sessile, 5-12 cm. long; inflorescence corymbose or 

 paniculate, glandular; involucre 1 cm. high, very glandular and long-yillous; 

 flowers yellow; akenes columnar; pappus fuscous. Common on hillsides. 

 Very variable in the amount and length of the pubescence. 



374. CENTAUREA. 



Herbs; heads many-flowered; flowers all with tubular and 

 deeply 5-cleft corollas, some of the marginal ones commonly 

 sterile, often much larger and conspicuous, the others perfect 

 and fertile; involucre globular, the scales tipped or margined 

 with spines or scarious appendages; receptacle very bristly; 

 pappus of numerous rigid or sometimes chaffy naked bristles; 

 akenes mostly compressed, attached by one margin just above 

 the base. 



Annual, white woolly; leaves linear or lanceolate, entire. C. cyanus. 



Biennial, green; leaves oblong to lanceolate, some dentate. C. consimihs. 



Centaurea cyanus L. Bachelor's Button. Stems erect, slender, usually- 

 branched, 30-90 cm. high; heads solitary on slender branches; involucre 



