COMPOSTTACEAE (COMPOSITE FAMILY) 235 



EE. Flowers white to red. 



F. Plant very white-woolly. U. C. occidentalis 



FF. Plant densely pubescent to glabrate. 



G. Inner involucre bracts with dilated tips. E. C. magnificus 



GG. None of the involucre bracts with dilated tips. 



H. Herbage pubescent, grayish or green; leaves weakly prickly; 10-30 dm. 

 high. W. C. E. A bad weed in waste places and logged off lands. 



C. edulis (EDIBLE THISTLE) 

 HH. Herbage glabrate, green; leaves strongly prickly; 6-9 dm. high. E. 



C. hallii 

 DD. Involucre bracts much shorter outward, appressed. 



I. Heads oblong or cylindric; inner involucre bracts purplish. E. C. andersoni 



II. Heads wider; inner involucre bracts not or very slightly purplish. 



J. Stem somewhat woolly; inner involucre bracts somewhat dilated. E. 



C. foliosus 



JJ. Stem glabrous; inner involucre bracts not dilated. E. C. drummondii 



CC. Involucre bracts with glandular ridge or spot on the back. 



K. Outer involucre bracts with spines nearly equaling the body. E. 



C. ochrocentrus (YELLOW-SPINED THISTLE) 



KK. Outer involucre bracts with spines distinctly shorter than the body. 

 L. Leaves canescent on both sides. E. undulatus 



LL. Leaves green above. 



M. Leaves conspicuously prickly. E. C. brewer! 



MM. Leaves with few prickles. E. C. palousensis 



BB. All the involucre bracts spine-tipped. W. E. Bad pasture weed. 



C. lanceolatus (BULL THISTLE) 



CENTAUREA (STAR THISTLE) 



Involucre bracts margined or appendaged ; receptacle bristly. Marginal 

 flowers sometimes suggesting rays, color various. Pappus none or bristles 

 or scales. (It is said that the centaur Chiron cured his wounded foot with 

 these.) 



A. Involucre bracts spine-tipped. 



B. Stem not winged; corollas purplish; pappus none. W. C. calcitrapa (CALTROPS) 

 BB. Stem winged; corollas yellow; pappus of unequal bristles or scales. W. 



C. meltensis (TOCALOTE) 

 AA. Involucre bracts not spine-tipped. 



C. Annual; pappus of unequal bristles; corollas white or red or blue or violet. E. 



C. cyanus (BLUE-BOTTLE) 

 CC. Perennial; pappus none; corollas red. E. C. consimilis 



CICHOREAE (Dandelion Tribe). Herbs, nearly always with milky 

 juice. Leaves alternate, often all basal. Heads involucrate; receptacle 

 flat or nearly so. Flowers all alike, perfect. Corolla strap-shaped, variously 

 colored, truncate but nearly always 5-toothed at apex. Anthers sagittate- 

 auriculate but not caudate at base. Style branches filiform minutely papil- 

 lose, not appendaged. 



A. Flowers yellow or orange or saffron-colored. 



B. Pappus none; stem leafy, branched; flowers in panicles; akenes 2o-3o-striate. 

 W. E. (The Greek name of some plant of the Mustard family.) 



Lapsana communis (NIPPLEWORT) 



