252 COMPOSITAE. 



ovoid; bracts in about four series, pale, the middle ones margined with a silvery 

 scarious-toothed border; ray flowers large, white, blue, pink or violet. A 

 common weed in fields and waysides. 



Centaurea consimilis Boreau. Perennial, 30-60 cm. high, rough-pubescent; 

 lower leaves oblong or spatulate, some dentate, petioled; uppper 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 

 introduced. 



375. PETASITES. SWEET COLTSFOOT. 



Perennial herbs with creeping rootstocks; leaves large, radical, 

 the cauline reduced to bracts; heads numerous in a raceme or 

 corymb on the end of a scape-like stem, with some imperfect 

 flowers; flowers whitish or purplish ; involucral bracts in one row; 

 akenes narrow, 5-10-ribbed, with soft white pappus. 



Petasites sagittata Pursh (P. dentata Blankinship). Leaves triangular- 

 ovate to hastate-reniform, coarsely sinuate-dentate, green above, densely 

 white-tomentose beneath, 1030 cm. long; flowering stems covered with large 

 scale-like leaves; heads in a dense convex cyme; flowers purplish, violet-scented. 

 In swamps, Spokane County and adjacent Idaho. 



376. GNAPHALIUM. CUDWEED. 



Woolly herbs; leaves alternate, entire; heads small, discoid; 

 pistillate flowers very numerous, in more than one row; perfect 

 flowers fewer in the center; staminate flowers none; all flowers 

 white or yellow; pappus-bristles slender, not thickened above; 

 akenes oblong or ovate. 



Plants low; flowers in dense leafy clusters; involucres very 



woolly. G. palustre. 



Plants tall; flowers in looser leafless clusters; involucres 



woolly only at base. 



Glandular; leaves green above. G. decurrens. 



Not glandular; leaves white- woolly. 



Involucre white; cymes loose. G. microcephalum. 



Involucre yellowish; cymes dense. G. chilense. 



Gnaphalium palustre Nutt. Annual, much branched at base, 5-12 cm. 

 high, very woolly throughout; leaves lanceolate, oblong or spatulate, 1-2 cm. 

 long; heads 2-3 mm. high, sessile, in small terminal or axillary clusters, which 

 are very woolly and subtended by leaves; involucre of few scales, these linear, 

 acute or obtuse, brownish with white tips; akenes glabrous, the bristles falling 

 separately. Common in dried-up pond bottoms. 



Gnaphalium decurrens californicum (DC.) Gray. Perennial, erect, 30-60 

 cm. high, glandular beneath a thin early-deciduous tomentum; basal leaves 

 spatulate; cauline spatula te-lanceolate or linear-lanceolate, acute, all con- 

 spicuously decurrent at the base, 2-5 cm. long; heads in dense clusters, these 

 usually corymbed; involucre turbinate-campanulate, yellowish-white; bracts 

 thin, scarious, ovate-lanceolate, mostly acute; akenes smooth. Open woods, 

 Thatuna Hills. 



