1024 CICHORIACEAE 



1 or 2 small calyculate ones. Achenes gradually tapering dowmvard from the 

 truncate summit, 4-5-ridged. Pappus of white soft capillary bristles. 



1. P. exigua (A. Gray) Rydb. Stem 1-2 dm. high, divaricately branched; 

 basal leaves spatulate or oblong in outhne, 2-3 cm. long; involucres 3-4 mm. 

 high; calyculate bracts small, ovate; bracts proper 4^5, oblong. Lygodesrnia 

 exigua A. Gray. Stony lulls: Tex.— Colo.— Utah— se Calif. Ap-Je. 



19. NABALUS Cass, Rattlesnake-root. 



Perennial caulescent herbs. Heads small, clustered, and usually nodding. 

 Involucre narrow, cylindric to caznpanulate; bracts narrow, in 1 or 2 subequai 

 series, subtended by a few small calyculate ones. Receptacle flat, naked. Flow- 

 ers pale, cream-colored or purplish. Achenes oblong or columnar, terete or 

 5-anglod, often 10-ribbed, sometimes slightly tapering towards the- base. Pap- 

 pus of numerous capillary, rather rigid, pale or bro\ra bristles. [Prenanthes 

 Vaul.] 



Basal loaves oblanceolato or spatulate; inflorescence Iiirsute. 1, N. racemosus 



Basal leaves cordate, sagittate, or hastate; inflorescence glabrous or puberulent. 



Leaves variously lobed or cleft; heads nodding; calyculate bracts ovate, very short. 



T J X X fl . , , 2. ^. albus. 



Leaves dentate; flowering heads not nodding: calyculate bracts linear, half as lone as 

 the bracts proper. 3. jv. sagittatus. 



1. N. racemosus (Alichx.) DC. Stem 5-10 dm. high, glabrous or pubes- 

 cent above; basal leaves glabrous, entire or dentate, with winged petioles; stem- 

 leaves sessile, oblong or elliptic, partly clasping; heads in a long spike-like thyrsus; 

 involucres campanulate, lJ-14-flowercd, 10-12 mm. high; bracts narrowly linear, 

 obtuse, hirsute; flowers rose or purplish; pappus fulvous. :Moist ground: N.B.— 

 N.J.— Colo.— Mont.— Alta. Plain— Mont Au-S. 



2. N, albus (L.) Hook. Stem 5-15 dm. high, glabrous, often tinged with 

 purple; leaves petioled; blades deltoid-hastate, denticulate, dentate, lobed, or 

 divided, or the upper lanceolate and entire, thin, glabrous, paler beneath; heads 

 numerous, paniculate, pendulous, about 12 mm. high and 6 mm. broad; prin- 

 cipal bracts about 8, purplish, linear; corollas greenish or white; pappus reddish 

 bro^\'n. Open woods: Me.— Ga,— Ky.^Minn.— Sask. Boreal Au-S. 



3. N. sagittatus (A. Gray) Rydb. Stem glabrous, 3-7 dm. high; lower 

 leaves petioled; blades sagittate, hastate or ovate, dentate or lobed, with lanceo- 

 late sahent lobes, glabrous, thin; upper leaves sessile, lanceolate, acuminate; 

 heads in a narrow panicle, at first erect, in fruit spreading or rarely somewhat 

 dcflexed; involucres about 12 mm. high; bracts linear, green; flowers tinged with 

 purjjle; pappus sordid. Along rivers: Mont.— Ida. SubmonL Jl^ 



20. CREPIS L. 



Annual, biennial 

 lindric or camnar 



Involucre 



thickened midrib- a small outer calyculum present or absent. Flowers yellow. 

 Achenes 10-30-ribbed, narrowed towards the summit. Pappus of nmnerous, 

 white and soft bristles. 



Plant neither canescent nor furfurascent; heads hemispherical to turbmate 



Inyolucres glabrous or tomentulose when young; neither Mrsute nor glandular 



in\oiucres giaorous or slightly puberulent when young. 2 C nlmira 



Involucres and peduncles hu-sute or glandular or both {/i"«c«. 



Plant 3-10 dm. high; heads few or many 



Leaf-blades oblanceolate or obiong to linear-oblanceolate 



Lea ves^long^etioled : petiolas half as long to fully as long a^ the blades. 



^'^iZ'Ai^^^^ broadly Oblanceolate; stem usuaUy wit^ 



^'"?aTe^'stemSi&^ 



laie, stem scapitorm, involucres less than 1 cm. high. 



Leaves subsessile or with short winged petioles ^' ^' ^^^^^^^^^• 



Leaves glabrous or nearly so; mvolucres with a few short hairs. 



5. C. perplexans. 



