234 ELEMENTS OF BOTANY. 



spatulate, pale beneath, the lower petioled and pinnatifid, the upper 

 sessile, clasping, and nearly entire ; heads numerous, about •20-flow- 

 ered ; flowers yellow; achenes oval, flat, ^ 1 -ribbed on each side, 

 minutely roughened, about as long as the beak; pappus white. 

 June-October. In waste places. 



2. L. viLLOSA Jacq. Blue Lettuce. Stem very leafy, smooth, 

 paniculately branched above, 3-6 ft. high ; leaves ovate to lanceo- 

 late, acuminate, often hairy beneath, the lower on winged petioles 

 and often sinuate-lobed, the upper sessile ; heads racemed, on diver- 

 gent and bracted peduncles ; flowers blue ; achenes slightly com- 

 pressed, beak very short; pappus white. June-September. In 

 waste places. 



VI. SITILIAS. 



Annual or biennial ; stem erect, leafy below, nearly naked 

 above, smooth ; leaves oblong, toothed or pinnatifid ; heads 

 large, long-peduncled ; involucre cylindrical or spreading, the 

 inner row of bracts erect, united at the base, the outer rows 

 shorter and spreading ; receptacle naked ; flowers yellow ; rays 

 truncate, 5-toothed at the apex ; achenes oblong, 5-ribbed, 

 narrowed above into a long and slender beak ; pappus soft, 

 tawny, with a short, villous ring at the base. 



S. Carolixiaxa (Walt.) Raf. False Daxdeliox. Annual or 

 biennial; stem glabrous, furrowed, branched above, 2-3 ft. high; 

 lower leaves lanceolate to oblong, entire, toothed or pinnatifid, nar- 

 rowed into a margined petiole, the upper sessile, bract-like, entire ; 

 heads few, long-peduncled, peduncles and involucre sometimes puberu- 

 lent ; inner bracts calloused at the apex, the outer subulate and 

 spreading; achenes much shorter than the filiform beak. April- 

 July. Common in fields. 



124. composit;e. thistle family. 



Herbs or shrubs, with watery or resinous juice; leaves 

 opposite, alternate or basal, entire, toothed, or divided, ex- 

 stipulate ; flowers in heads surrounded by an involucre of 

 bracts in 1 or more rows ; the receptacle naked or chaffy, 

 smooth or pitted, concave, flat or convex ; flowers perfect or 

 variously imperfect ; calyx tube adnate to the ovary, the 

 limb prolonged above into a pappus of scales, bristles or 



