922 CARDUACEAE 



Bristles of the pappus not united at the base, falling off separately. 



Heads not leafy-bracted ; involucral bracts well imbricate, scarious, white or tinged 



with brownish, rose, or yellow; plants mostly tall. 

 Leaves tomentose on both sides; plants little if at all glandular; involucres tomen- 



tose at the base. 



Stem-leaves narrowed at the base, neither decurrent nor clasping. 



Perennial or biennial; stem 3-5 dm. high; inaorescence open; bracts white. 



1. G. Wrightii. 

 Annual; stem 1-2 dm. high; inflorescence dense; bracts yellowish. 



2. G, thermale. 

 Stem-leaves not narrowed at the base, more or less decurrent, or at least 



auricled-clasping . 



Leaves with short broad adnate auricles at the base; bracts obtiise. 



Heads 5-6 mm. high, niunerous, in glomerules ending the short spread- 

 ing branches; bracts shghtly if at all yellowish; plant tall; stem- 

 leaves lanceolate or oblong, with rounded bases, cuspidate. 



3. G. proximum. 

 Heads 4 mm. high, few, in small glomerules, ending the stem or few- 

 erect branches ; bracts decidedly yellowish when young ; plant low ; 

 leaves oblong to linear, merely acute or obtuse. 



Stem erect, strict; lower stem-leaves oblong-oblanceolate. 



4. G. sulphur escens. 



Stem decumbent at the base; lower stem-leaves spatulate, 



_ 5. G. lagopodioides. 



. Leaves distinctly decmrent; bracts acutish; heads 4-5 mm. high. 



Bracts broadly ovate; inflorescence corymbiform. 6. G. Williamsii. 

 Bracts lance-ovate; inflorescence narrow. 7. G. mi croc epha turn. 



Leaves on the upper surface green and decidedly glandular, decurrent; involucres 

 TT ^ glabrous. 8. G. Macounii. 



Heads leafy-bracted; mvolucral bracts little imbricate, brown or greenish; plant low; 



involucre floccose at the base. 

 Plants loosely floccose; leaves broad, spatulate, oblong or oblanceolate. 



Plants appressed-tomentose; leaves except the lowest narrowly oblanceolate or 



linear. 



Stem diffusely branched; glomerules crowded, cymosely disposed. 



Upper leaves narrowly oblanceolate. 10. G. uliginosum. 



Upper leaves narrowly linear. II. G. exili folium. 



Stem mostly simple, erect; glomerules spicately disposed. 



T> • xt * XT- . 12. G. Grayi. 



Bristles of the pappus muted m a ring at the base and falling off together; leaves ob- 

 lanceolate or spatulate. 13. g. ustulatum. 



• 1,^' ^' ^^^^^^^^ -^' Gray. Biennial or perennial, with a taproot; stem up- 

 right, much branched above, -white-floccose throughout; leaves oblanceolate or 

 spatulate, 2-A cm. long, the uppermost linear; heads numerous in a rather open 

 panicle; mvolucres 5-6 mm. high; bracts white, oblong, abruptly pointed, pearly 

 white. G. albalum Osterh. Dry grounds: Colo.— N.M.— Calif. SubmonL Au-0. 



2. G. thermale E. Nels. Annual; stem low, branched from the base, 

 grayish-tomentose; basal leaves oblanceolate, about 3.5 cm. long; stem-leaves 

 narrowly oblanceolate to linear, 1-3 cm. long; heads sessile in small glomerules, 

 termmating the branches; involucres 4-5 mm. high; bracts dull white or yellow- 

 ish, the outer ovate, the innermost linear, abruptly apiculate. G. Wrightii Coult. 

 & Nels., not A. Gray. Hot-spring formations: n Wyo. Mont. Jl. 



3. G. proximum Greene, Biennial or annual, with a taproot, branched at 

 the base; stem 3-6 dm. high, very leafy; basal leaves spatulate or oblanceolate, 

 3-4 mm. long; inflorescence closely paniculate, leafy-bracted; involucres villous, 

 576 mm. high; bracts straw-colored or ochroleucous, obtuse. Perhaps scarcely 

 distmct from G. Chilense Spreng. Wet places: Wyo.— Utah— Nev.— Wash. 

 Suhmoni, — Mcmt, Jl-Au. 



4« G. sulphurescens Rydb. Annual or biennial; stem usually simple, 

 2-4 dm. high, often yellowish above; basal leaves spatulate, 2-3 cm. long, white- 

 woolly; stem-leaves hnear or the lower oblong-spatulate, mostly erect; heads 

 sessile m small glomerate c^^nes; involucres 4-5 mm. high; bracts elliptic or oval, 

 very obtuse, yellow, glossy. G, luteo-album Hook., not L. Wet sandy soil: 

 Mont.— Tex.— N.M.— Wash. Jl-N. 



6, G. lagopodioides Rydb. Biennial, usually branched at the base; stem 

 about 1 dm. high, densely woolly-tomentose; basal leaves spatulate, 1-1.5 cm. 

 long, loosely woolly; stem-leaves oblong-spatulate or the low^er obovate-spatulate; 

 heads in small conglomerate cymes; involucres about 4 mm. high; bracts oblong 



