COMPOSIT.E. (COMPOSITi: FAMILY.) 170 



1. S. laciniatum, L. Stem 3 to 6 and even 12 feet high: radical leaves 

 a foot or two long, long-petioled, once or twice pinnatoly parted or helow 

 divided, tlie divisions and lobes lanceolate to linear; canline with petiole sim- 

 ply dilated at I)ase, or with sti]iuliforni and sometimes palmatifid appendages; 

 upper sessile and reduced to hracts: involucre inch or more high and hroad : 

 rays numerous, inch or two long, l)right yellow. — Prairies, from the Dakotas 

 to Texas aud eastward to Wiscousiu and Alabama. 



23. PARTHENIUM, L. 



Ours is an acaulescent cespitose perennial, with the ligule wanting. 



1. P. alpinum, Torr. & Gray. Den.sely tufted on a thick branching cau- 

 dex, depres.sed, rising only 1 or 2 inclies : leaves crowded, silvery -cane.<cent with 

 a fine ajjjiressed pubescence, and villous in the axils, spatulate-lincar, barely an 

 inch long, entire: heads solitary and nearly se.^sile among the leaves: j)appus 

 a pair of oblong-lanceolate membranaceous scales. — Mountains of Wyoming. 



24. PARTHENICE, (iray. 



Allied to both Parthenium and led. 



1. P. mollis, Gray. Annual, Avith odor of Artemisia, 4 to 6 feet high, 

 panicularely branched, minutely cinereous throughout, wholly destitute of any 

 coai\«;er ]>ubescence : leaves all alternate, ovate, some of the larger (10 or 12 

 inches long) subcordate, acuminate, irregularly or doubly dentate, long-peti- 

 oled : heads small, 2 lines broad, numerous in loose axillary and terminal 

 somewhat leafy panicles : flowers greenish-white. — S. Colorado to Arizona. 



25. IV A, L. 



Herbs or slirubs . with entire or serrate leaves, at lea-^t the lower ones oppo- 

 site, and small spicatel\ or racemosely or paniculately disposed or scattered 

 aud commonly nodding heads. 



* Heads crowded in narroio briike-like clusters trln'ch are arjfjre'jaled in a naked 



jHimcle : /eaves lomj-petioled. 



1. I. xanthiifolia, Xutt. Tall and coar.se, .3 to 5 feet high, pnbe.^cent, at 

 least when young : leaves mainly opposite, broadly ovate, ample, coai-sely or 

 incisely serrate, acuminate, .3-ribbed at base, puberulently jicabrous above: 

 panicles axillary and terminal : outer involucral bracts 5, broadly ovate and 

 herbaceous; inner of as many membranaceous dilated-obovate or truncate 

 ones, which are strongly concave at maturity and half eml)race the obuvate- 

 pyriform and glabrate akenes. — From New Mexico to Idaho aud the Sas- 

 katchewan. 



* * Head-: spicateli/ or racemosehj disposed in (he axils of leaves or /oliaceous 



bracts, and nodding. 



2. 1. Ciliata, Willd. Rather stout, 2 ^o 6 feet high, strigo.sc and hispid : 

 leaves nearly all opposite, ovate^ acuminate, sparsely serrate, the base abruptly 

 contracted into a hispid petiole: spikes strict, 3 to 8 inches long, their bracts 

 lanceolate and ovate-lanceolate, foliaceous, surpassing the at length deflexed 

 heads, hispid-ciliate, as are the 3 or 4 herbaceous and unequal distinct or partly 

 united bracts of the involucre — From New Mexico to Nebraska aud eastward 



