304 coMPOsiTiE. (composite family.) 



pus, its bristles falling separateh^ — Leafy-stemmed herbs, with panicled heads ; 

 flowers of variable color, produced in summer and autumn. (The ancient 

 name of the Lettuce, L. satica ; from lac, milk, in allusion to the milky juice.) 



§ 1. SCARtOLA. Achenes verij flat, orbicular to oblong, l-nerved on each face, 

 icitli aflUform beak; biennial or annual ; cauline leaves sagittate-clasping. 



L. ScARiOLA, L. (Prickly Lettuce.) Stem below sparsely prickly- 

 bristly, as also the midrib on the lower face of the oblong or lanceolate spinu- 

 lose-denticulate vertical leaves ; panicle narrow ; heads small, G - 1 2-flowered ; 

 achenes striate. — Waste grounds and roadsides, Atlantic Slates to Mo. and 

 Minn. (Adv. from Eu.) 



1. L. Canadensis, L. (Wild Lettuce.) Mostly tall (4-9° high), 

 very leafy, smooth or nearly so, glaucous; leaves 6-12' long, pale beneath, 

 mostly sinuate-pinnatitid, the upper lanceolate and entire (rarely all but the 

 lower narrow and entire) ; heads about 20-tlowered, 3 - 6" long, numerous, in 

 long and narrow or diffuse panicles ; flowers pale yellow ; achene oval, rather 

 longer than the beak. — Rich damp soil, borders of fields or thickets ; common. 



2. L. integrifdlia, Bigel. Less leafy, 3-4° high, loosely branched 

 above or heads loosely panicled ; leaves undivided, oblong-lanceolate, pointed, 

 denticulate or entire ; flowers yellow or purplish. (L. Canadensis, var. integ- 

 rifolia, Torr. cj- Graij.) — N. Eng. to 111., and southward. 



3. L. hirsuta, Muhl. Rather few-leaved, 2-3° high, commonly hirsute 

 at base ; leaves hirsute both sides or only on the midrib, mostly runcinate-pin- 

 natifid ; heads in a loose open panicle ; achenes oblong-oval, about as long as 

 the beak; flowers yellow-purple, rarely whitish. (L. Canadensis, var. san- 

 guinea, Torr. cj- Gratj.) — E. Mass. to Minn., and southward. 



4. L. Ludoviciana, DC. Glabrous, leafy, 2-5° high; leaves oblong, 

 sinuate-piunatifid and spinulosely dentate, ciliate ; heads in an open panicle ; 

 involucre more imbricate ; flowers yellow. — Minn., Iowa, and southwestward. 



§ 2. LACTUCASTRUM. Achenes flat, lanceolate-oblong, tapering to a short 

 slender beak ; perennial ; flowers blue. 



5. L. pulchella, DC. Pale or glaucous; stem simple, 1-2° high; 

 leaves sessile, oblong- or linear-lanceolate, entire, or the lower runcinate-pin- 

 natifid ; heads few and large, racemose, erect on scaly-bracted peduncles ; in- 

 volucral scales imbricated in 3 or 4 ranks. (Mulgedium, Nutt.) — Upper Mich, 

 to Minn. ; common on the plains westward. 



§ 3. MULGEDIUM. Achenes thickish, oblong, contracted into a short thick 

 beak or neck ; annual or biennial ; flowers chiefly blue. 



6. L. acuminata, Gray. Tall biennial (3-7° high), with many small 

 heads in a loose panicle, on diverging peduncles ; leaves ovate to oblong-lan- 

 ceolate, pointed, sharply and sometimes doubly serrate, sometimes hairy on 

 the midrib beneath, contracted into a winged petiole, the lowest occasionally 

 sinuate or cleft at base, and the cauline sagittate or hastate ; achenes beak- 

 less; pappus white. (Mulgedium, DC.) — Borders of woods, N. Y. to 111. 

 and Fla. 



7. L. Floridana, Gaertn. Leaves all lyrate or runcinate, the upper 

 often with a heart-shaped clasping base; panicle larger; achenes distinctly 

 beaked ; otherwise as n. 6. — Rich soil, Penn. to 111., and southward. 



