MONOPETALOUS EXOGENOUS PLANTS. 335 



S. DiscoiDEA, ToiT. and Gray. Stem 3°-5° high, simple 

 or branched, pubescent or liairy ; leaves ovate, acute, 

 abruptly narrowed into a petiole, lower ones serrate ; 

 achenia smooth ; racemes 3-G, large, 10-l§-flowered heads ; 

 rays none ; floiuers yellowish white. 



ViRGAUREA. Scales of the involucre appressed ; rays 

 mostly fewer than the dask-flowers, rarely wanting ; racemes 

 racemose-corymbose, or panicled. 



* Racemes not 1-sided ; leaves feather-veined. 



t Racemes crowded in racemose or pyramidal terminal panicles, longer than the 

 leaves; lowest leaves large, commonly tapering into a petiole, the uppermost 

 small, sessile and entire. 



S. PETiOLARis, x\it. Minutely pubescent ; stem mostly 

 simple, straight, very leafy; leaves oblong-lanceolate or 

 elliptical, acute, rough on the margins, all but the low^est 

 entire, and nearly sessile ; panicle racemose or oblong ; 

 heads large, 20-25 -flowered ; rays about 10, showy ; scales 

 of the involucre linear, pubescent, the outer ones more or 

 less spreading; achenia smoothish. Stem 2°-3° high ; 

 leaves l'-2' long. 



S. SPECiosA, Nutt. Stem stout, mostly simple, smooth 

 below, pubescent above; leaves smooth, the lowest large 

 (5'-8' long, l-J'-2' wide), serrate, the upper ones lanceo- 

 late ; panicle compact, pyramidal ; heads rather large, 

 crowded, 15-20-flowered ; rays 6-8, showy; scales of the 

 involucre lanceolate, obtuse; achenia smooth. — Varies, 

 Avith the stem and lower surface of the broader (2-3') 

 leaves villous ; the fewer, larger, and more scattered heads 

 about 30-flowered ; or every way smaller ; the short 

 racemes forming a narrow racemose panicle. The first 

 variety only in the upper districts. Stem 3°-5° high, 

 often purplish. 



