1036 C1CHORIACEAE 



Heads 12-20-flowered; achenes 1-3-nerved, transversely rugose. 

 Involucres about 1 cm. high. 



Leaves linear-lanceolate, perfectly entire. 3. L. polyphyUa. 



Leaves pinnatifid or lobed, at least some of them. 4. L. canadcnsis. 

 Involunv- \.~l-2 cm. high. 



Leaves obovate or oblanceolate in outline, with broad lobes, often spinulose 



on the midribs beneath. 5. L. ludoviciana. 



Leaves linear or linear-lanceolate in outline, entire or with narrow lobes, 



never spinulose. 6. L. graminifolia. 



Bracts in 5-6 series, gradually increasing upwards, a distinct calyculum therefore not 



evident; flowers blue. 7. L. pulchella. 



Achenes beakless; pappus tawny or brown. 



Lobes of the leaves broadly triangular or ovate, sinuately and saliently dentate. 



8. L. spicata. 

 Lobes of the leaves lanceolate or linear, again 1-3-lobed. 9. L. multifida. 



1. L. virosa L. Biennial, with a branched root; stem erect, 5-20 dm. high, 

 more or less hispid towards the base; leaves numerous, oblong or oblanceolate, 

 obtuse or mucronate, horizontal, 1-3 drn. long, spinulose-denticulate, sessile and 

 clasping; panicle loosely branched; involucres 10-12 mm. high, 4-6 mm. broad; 

 bracts in about 4 series, lanceolate, thick; flowers light yellow, turning bluish; 

 achenes with broader margins than those of the next. L. integrata A. Nels. 

 Waste places and fields: Me. Ga. Calif. B.C. ; nat. or adv. from Eu. Plain 

 Suhtnonl. Je-S. 



2. L. Scariola L. Biennial, with a branched root; stem 3-10 dm. high, 

 sparingly prickly-bristly below; leaves pinnatifid or lobed, rarely merely sinuate, 

 tending to turn edgewise into a vertical position; involucres ovoid-cylindric, 

 about 10 mm. high, 4 mm. broad; bracts imbricate in about 4 series, lanceolate 

 or the inner linear-lanceolate; flowers yellow, turning bluish; achenes elliptic- 

 oblanceolate, slightly margined, 5-nerved on each side. Fields and waste places: 

 Mass. Tenn. Calif. B.C.; nat. from Eu. Jl-Au. 



3. L. polyphylla Rydb. Biennial; stem about 1 m. high, glabrous; leaves 

 sessile, slightly auric ulate-clasping, very numerous, linear-lanceolate, entire, 

 acuminate, 1-2 dm. long, glabrous; involucre about 1 cm. high; outer bracts 

 lanceolate, the inner linear-lanceolate; achenes nearly black, 3-4 mm. long, in- 

 distinctly 3-nerved, transversely rugose. Meadows: Ida. Submont. Au. 



4. L. canadensis L. Biennial; stem 1-3 m. high, often mottled, glabrous 

 or nearly so ; basal leaves mostly spatulate or oblong, dentate or pinnatifid ; stem- 

 leaves 1-3 dm. long, sinuately pinnatifid; involucres 10-12 mm. high; outer bracts 

 lanceolate, inner linear; flowers yellow; achenes oval-oblong, almost black, 

 transversely rugose, 3-nerved. Moist places: N.S. Fla. Colo. Sask. Alta. 

 Plain Submont. 



5. L. ludoviciana (Nutt.) DC. Biennial; stem 5-15 dm. high, glabrous; 

 leaves oblong-oblanceolate in outline, sinuately lobed or pinnatifid, with rounded, 

 ovate or lanceolate, spinulose-denticulate lobes; involucres 15-20 mm. high; 

 outer bracts ovate, the inner linear-lanceolate, scarious-margined ; flowers yellow ; 

 achenes brown or black, 4 mm. long, broadly oval or obovate, 3-ribbed, obscurely 

 transversely rugose. River-banks and wet places: Minn. Mo. Tex. Colo.- 

 Mont. Plain Submont. Jl-S. 



6. L. graminifolia Michx. Biennial or perhaps perennial; stem 5-15 dm. 

 high, glabrous; leaves glaucescent, elongated linear or linear-oblanceolate, 1-4 

 dm. long, entire or sinuately lobed or pinnatifid with narrow, spreading or de- 

 flexed lobes; involucres 12-15 mm. high; outer bracts lanceolate, the inner linear- 

 lanceolate, scarious-margined; flowers yellowish, white or purplish; achenes 

 elliptic, 4-5 mm. long, 3-nerved, black. Rich soil: N.C. Fla. Ariz. Colo. 

 Son. Submont. Ap-S. 



7. L. pulchella (Pursh) DC. Perennial, with a deep rootstock; stem 3-10 

 dm. high, glabrous; leaves linear-lanceolate, lanceolate, or oblong, acute, entire, 

 dentate or even some of them pinnatifid, 5-20 cm. long, somewhat glaucous; 

 panicle usually narrow; involucres 16-20 mm. high; flowers blue; achenes oblong- 

 lanceolate, about 4 mm. long, rather strongly 3-nerved on the faces, gradually 

 tapering into the short beak. L. sylvatica A. Nels. Wet meadows: Sask. Mo. 



-X.M. Calif. B.C. Plain Submont. Mv-Au. 



