252 
SYNGENESIA &QUAL1S. 
LACTUCA. Gen. Pe. 1234. 
Involucrum imbrica- 
tum, cylindricum, mar- 
gisie membranaceum. 
Semina laevia. Pap- 
pus simplex, stipitatus. 
Receptaculum nudum. 
Involucrum imbri- 
cate, cylindrical, the 
scales membranaceous 
along the margin. 
Seeds smooth. s Pap- 
pus' simple, stipitate. 
Receptacle naked. 
1. Elongata. Muhl. 
L. foliis subtus laevi- 
bus, inferioribus run- 
cinatis, integerrimis, 
amplexicaulibus, infi- 
mis dentatis, summis 
lanceolatis; floribus 
corymboso-paniculatis. 
Leaves smooth un- 
derneath, the lower 
runcinate, entire, am- 
plexicaule, the lowest 
toothed, the uppermost 
lanceolate; flowers in 
corymbose panicles. 
Sp. pi. 3. p. 1525. Pursh, 2. p. 500. Nutt. 2. p. 124. 
L. Caroliniana. Walt. p. 193. 
L. Longifolia. Mich. 2. p. 85. 
Root perennial? Stem four to seven feet high, glabrous. Leaves very 
long, glabrous, conspicuously runcinate. Flowers in a large terminal pani- 
cle, composed of small corymbiform clusters. Involucrum imbricate, the 
interior leaves long, appressed until the seed matures, then reflected. Flo- 
rets numerous. Corolla ligulate, yellow. Seed compressed, crowned with 
a stipitate, hairy pappus. 
Grows in rich and damp soils. 
Flowers July — September. 
2. Graminifolia. Mich. 
L. caule erecto, sim- 
plici; foliis inermibus, 
plerisque indivisis, ba- 
si simplici, longissime 
linearibus; panicula 
Stem erect, simple; 
leaves unarmed, gene- 
rally undivided, simple 
at base, long, narrow; 
panicle leafless, loose. 
