GENUS 23. 



CHICORY FAMILY 



7. Nabalus Boottii DC. Boott's Rattle- 

 snake-root. Fig. 4116. 



Nabalus Boottii DC. Prodr. 7: 241. 1838. 

 Prenanthes Boottii A. Gray, Syn. Fl. i : Part 2, 435. 

 1884. 



Glabrous below, commonly pubescent above; 

 stem simple, 4'-i2' high. Leaves thickish, the 

 basal and lower ones ovate, hastate, or deltoid, 

 petioled, mostly obtuse, entire, or denticulate, i'-2' 

 long, the upper ovate or oblong, usually entire, 

 short-petioled or sessile, much smaller; heads 

 several or numerous, io-i8-flowered, erect, spread- 

 ing, or some of them pendulous, racemose or 

 somewhat thyrsoid, 4"-5" broad ; involucre cam- 

 panulate-oblong, 2j"-3" thick, 4,"-j" long, dark 

 purplish-green, its principal bracts 8-10, obtuse or 

 obtusish, with several shorter outer ones; flowers 

 whitish, odorous; pappus brownish. 



Alpine summits of the mountains of northern New 

 England and New York. July-Aug. 



8. Nabalus asper (Michx.) T. & G. Rough 

 White-lettuce. Fig. 4117. 



Prenanthes aspera Michx. Fl. Bor. Am. 2: 83. 1803. 

 Nabalus asper T. & G. Fl. N. A. 2 : 483. 1843. 



Scabrous or rough-puberulent ; stem virgate, simple, 

 2-4 high. Leaves firm, oval, oblong, or oblanceolate, 

 those of the stem all closely sessile, acute or acutish, 

 dentate, denticulate, or the uppermost entire, the lower 

 sometimes clasping, 2'-3' long, i'-i' wide, the basal 

 tapering into winged petioles, commonly obtuse ; heads 

 very numerous, erect, spreading, or slightly drooping, 

 3"~4" broad, i2-i6-flowered, in a long narrow thyrsus; 

 involucre oblong, 2"-2i" thick, 5 "-7" high, very hirsute, 

 its principal bracts 8-10, with several short outer ones; 

 flowers light yellow; pappus straw-color. 



On dry prairies, Ohio to South Dakota, Nebraska, Ken- 

 tucky, Louisiana and Kansas. Rattlesnake-root. Aug.-Sept. 



Glaucous White-lettuce. 

 1803. 



9. Nabalus racemosus (Michx.) DC. Glaucous White-lettuce. Fig. 4118. 



Prenanthes racemosa Michx. Fl. Bor. Am. 2 : 83. 



Nabalus racemosus DC. Prodr. 7: 242. 1838. 



Nabalus racemosus pinnatifidus Britton ; Britt. & Brown, 



111. Fl. 3: 291. 1898. 

 Prenanthes racemosus var. pinnatifida A. Gray, Syn. Fl. 



i : Part 2, 433. 1884. 



Stem virgate, rather stout, glabrous and somewhat 

 glaucous; stem striate, 2-6 high. Leaves thickish, 

 glabrous and glaucous, the lower and basal ones oval, 

 oblong, oblanceolate, or obovate, dentate, denticulate, 

 pinnatifid or pinnately lobed, 4'-8' long, mostly ob- 

 tuse, tapering into long margined petioles; upper 

 leaves sessile, smaller and partly clasping, lanceo- 

 late to ovate-lanceolate, denticulate, entire, or pin- 

 natifid, mostly acute; heads very numerous, erect, 

 spreading, or slightly drooping, i2-i6-flowered, 2"-3" 

 broad, in a long narrow thyrsus ; involucre oblong- 

 cylindric, hirsute, 5 "-6" long, i$"-2i" thick, longer 

 than the hirsute peduncle, its principal bracts 8-10, 

 with several small outer ones ; flowers purplish ; 

 pappus straw-color. 



In moist open places, New Brunswick and Quebec to 

 Maine, Manitoba, Alberta, southern New York, New 

 Jersey, Iowa, Missouri and Colorado. Aug.-Sept. 



Prenanthes mainensis A. Gray, from northern Maine and New Brunswick, is probably a hybrid 

 between N. racemosus and N. trifoliolatus* 



