252 COMPOSITE, (composite family.) 



ribbed or angled, muricate on the ribs ; the apex abruptly produced into a long 

 beak. Pappus of copious white hairs. — Stemless perennial herbs. Scapes hol- 

 low, bearing a single head of yellow flowers. Leaves all radical, oblong ot 

 lanceolate, entire or pinnatifid. 



1. T. Dens-leonis, Desf. Leaves pinnatifid, the lobes acute, toothed; 

 heads showy. — Damp soil, sparingly naturalized. 



88. PTRRHOPAPPUS, DC. 



Heads many-flowered. Involucre double, of numerous subulate scales ; the 

 inner ones erect and partially united, often with a callous appendage at the apex. 

 Receptacle flat, naked. Achenia oblong, nearly terete, 5-furrowed ; the apex 

 narrowed into a long filiform beak. Pappus of copious soft reddish or brownish 

 hairs. — Smooth annual herbs. Leaves oblong or lanceolate, commonly toothed 

 or pinnatifid. Heads solitary, terminating the naked stem or peduncle-like 

 branches. Plowers yellow. 



1. P. Carolinianus, DC. Stem branching ; leaves lanceolate, mostly 

 toothed or pinnatifid ; achenia shorter than the filiform beak. (Borkhansia, 

 Ell.) — Fields, Florida to Mississippi, and northward. April - July. — Stem 

 10-2° high. 



89. LACTUCA, L. Lettuce. 



Heads few- or many-flowered. Scales of the cylindrical involucre imbricated ; 

 the outer ones short. Receptacle naked. Achenia compressed parallel to the 

 scales, smooth, abruptly narrowed into a filiform beak. Pappus of copious soft 

 white hairs. — Tall herbs, with entire or pinnatifid leaves. Heads paniculate. 

 Flowers white, purple, blue, or yellow. 



1. L. elongata, Muhl. Smooth or nearly so; stem tall (4° -8°), simple 

 or paniculate ; leaves elongated, lanceolate, sessile or partly clasping ; the upper 

 ones mostly entire ; the lower pinnatifid ; panicle long, leafless ; flowers yellow. 

 — Var. INTEGKIFOLIA. Leaves all undivided, or the lowest pinnatifid ; flowers 

 yellow or purplish. — Var. graminifolia. Smaller (2°- 3°), leaves linear or 

 linear-lanceolate, rather rigid, all entire, or the lowest ones sparingly toothed 

 or pinnatifid; flowers purple. — Dry soil, Florida, and northward. July -Sept. 



90. MULGEDIUM, Cass. 



Heads many-flowered. Scales of the involucre imbricated, the outer ones 

 short. Receptacle naked. Achenia smooth, laterally compressed, nan-owed into 

 a short beak, which is expanded into a ciliate disk at the apex. Pappus of co- 

 pious white or tawny hairs. — Tall herbs. Leaves pinnatifid or undivided. 

 Flowers mostly blue. 



* -PopysMS white. 



1. M. acuminatum, DC. Smooth; stem panicled above ; leaves ovate 

 or ovate-laricfedlate, acuminate, toothed, on winged petioles, the lowest some- 

 times sinuate-lsbcd ; heads racemcd, on spreading peduncles. (Sonchus, Ell) 



