MOXOPETALOUS EXOGENOUS PLANTS. 355 



LEPTOPODA, Nutt. 



Heads maDy-flowered, radiate, the rays neutral, 3-4-cleft ; 

 cUsh-fiowers 4:-5-toothed; scales of the involucre in 1-2 

 rows, spreading, the exterior leafy, numerous, the interior 

 short and chaffy; receptacle conical or hemispherical, 

 naked ; achenia short, truncate at each end, striate ; papims 

 of 6-12 scarious toothed or fimbriate scales. — Perennial 

 lierls ; stems mostly simple, naked above ; leaves alternate ; 

 heads solitary ; flowers yellow or purple. 



* stems commonly simple, dilated under the head ; dlsk-Jlowers yellow ; rays 20 or 



more. 

 t Achenia smooth. 



L. INC ISA, Torr. and Gray. Smooth; leaves lanceolate, 

 rather obtuse, sessile, not decurrent, sinuate-pinnatitid or 

 incised; scales of the pappus lacerate, or slightly fimbriate 

 at the summit ; 7'ai/s about 40, in 2-3 roAvs. 



tt Achenia hairy on the angles. 



L. FIMBRIATA, Torr. and Gray. Stem smooth, some- 

 times branching, the peduncle slightly pubescent; leaves 

 linear-lanceolate, acute, entire or obscurely serrate, decur- 

 rent; scales of the pappus fimbriate. Stem l°-2° high. 



L. PUBERULA, Macbride. Closely pubescent; leaves 

 somewhat fleshy, linear-lanceolate, sessile but not decur- 

 rent, denticulate, tlie lowest spatulate-lanceolate, toothed 

 or pinnatifid; scales of the pappus obtuse, with slightly 

 lacerated margins. Stem 2° high. 



MARSHALLIA, Schreb. 



Heads many-flowered ; the flojuers all tubular and per- 

 fect; corolla pubescent, with linear spreading lobes; scales 

 of the involucre oblong-linear or lanceolate, in 1-2 rows; 

 chaff of the convex or conical receptacle narrow-linear, 



