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 or 

 lanceolate, entire or pinnatifid. 



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

 heads showy. Damp soil, sparingly naturalized. 



88. PYRRHOPAPPUS, 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. Flowers yellow. 



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

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

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

 l-2high. 



89. LACTUCA, L. LETTUCE. 



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

 the outer ones sliort. 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 5 leaves elongated, lanceolate, sessile or partly clasping ; the upper 

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

 Var. INTEGRIFOLIA. 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, narrowed 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. 



* Pappus white. 



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

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

 times sinuate-lobed ; heads racemed, on spreading peduncles. (Sonchus, Ell.) 



