■^''•«- COMPOSIT.E. 245 



roundish and obtuse lobes: heads numerous, paniculate-cymose: ligules commonly longer 

 than broad : pappus a pair of short-sul.ulate erect or at length spreading awns. — Xov Gen 

 & Spec. IV. 260, t. 391 : Gray, PI. Wright, i. 103. P. iucanum & P. ramosissimam, DC. Prodr. 

 ^. .5.32. — Dry hills, \V. Texas to Arizona. (Mex.) 

 P. argentatum, Geay. Suffrutescent, a foot high, silvery-canescent with close tomentum : 

 branches erect, rather leaflets above, bearing comparatively large and few heads (of 2 lines 

 m diameter) : leaves lanceolate to spatulate in outline, some entire or inci.'-ely 2-.')-tuothed • 

 the larger incisely pinnatifid into 2 to 7 acute lateral lobes : pappus a pair of lanceolate 

 chaffy awns. — Bot. Mex. Bound. 86. — S. \\. borders of Texas, Blgdow. (Adj. Mex., 

 Parry, Palmer. Produces a gum or resin in :\Iexico.) 



* * # Perennial herb, with larger heads and leaves ; the latter undivided, thickish. 

 -■P. integrifolium, L. Stout, l to 3 feet high, minutely pubescent, corymboselv branched 

 above, the branches terminated by a dense cyme of many heads (these a quarter-inch higl 



li : 



, — „.„„.... ^., ..^*.^.^.,c*./^^t ,_._y a. Licjinc u \ luc uL luiiny ueaus ^Gnese a quarcer-incn niglij : 



leaves ovate-oblong or narrower, thickly crenate-deutate," rarely doubly dentate or somewhat 

 incised, hispidulous-scabrous, prominently leiuy from a strong midrib; radical a foot or 

 more long and tapering into a petiole ; upper cauline closely sessile and broad at base : pap- 

 pus a pair of small chaffy teeth or scales. — Spec. ii. 988 (Dill. Elth. t. 225 : Pluk. Aim. t. 53 

 & 219) ; Lam. 111. t. 766 ; Willd. Hort. Berol. t. i ; Torr. & Gray, I. c. — Dry ground, Mary- 

 laud to Illinois and Texas. 



§ 2. BoLOPHTTUM, Torr. & Gray. (Bohphjta, Nutt.) Ligiile wanting, the 

 corolla being reduced to a truncate tube, which is obscurely notched at back and 

 front : acaulescent cespitose perennial. 



P. alpinum, Tore. & Gray, 1. c. Densely tufted on a thick branching caudex, depressed, 

 rising only an inch or two high : leaves crowded, silvery-canescent with a flue apprei^sed 

 pubescence, and villous in the axils, spatulate-linear, barely inch long, entire: lieads solitary 

 and nearly sessile among the leaves : pappus a pair of oblong-lanceolate membranaceous 

 scales. — Bolophyta a/;:i(«a, Nutt. Trans. Am. Phil. Soc. n. ser. vii. ,347. — Eocky Mountains 

 in AVyoming (at 7,000 feet), on rocks near the Three Buttes, Xuttall. 



76. PARTH:6NICE, Gray. {UapO^viK^, a poetical form of the word 

 from which the name of the preceding nearly related genus is derived.) ■ — PI. 

 "Wright, ii. 85 ; Benth. & Hook. Gen. 3.J2. — Genus of a single species, allied 

 also to the succeeding genus. 



P. mollis, Gkay, 1. c. Annual, with odor and savor of Artemisia, 4 to C feet high, panicu- 

 lately branched, minutely puberulent-cinereous throughout, wholly destitute of any coarser 

 pubescence: leaves membranaceous, all alternate, ovate, some of the larger (iis much as 10 

 or 12 inches long) subcordate, acuminate, irregularly or doubly dentate, long-petioled : heads 

 small (2 lines broad), numerous in loose axilkiry and terminal somewhat leafy panicles, 

 mostly pedicellate : flowers greenish-white. — Hillsides and along streams, S. Colorado to 

 Arizona, Wrigid, Thurber, Lemmon, &c. PI. autumn. 



77. IVA, L. (An unexplained name.) — American herbs or shrubs ; with 

 entire or dentate or dissected leaves, at least the lower ones opposite, and small 

 spicately or racemoselj' or paniculately disposed or scattered and commonly 

 nodding heads: fl. summer.' — Lam. 111. 7GG; Geertn. Fruct. t. 164; DC. Prodr. 

 V. 529. Ii-fj & Cijflachana (Frcsen.), Torr. & Gray, Fl. ii. 285 ; Benth. & 

 Hook. Gen. ii. 352. 



§ 1. Cyclach^na. Heads naked-paniculate, inconspicuously braoteate : co- 

 rolla of the 5 fertile flowers a very short rudiment or none : leaves membranaceous, 

 from incisel}- serrate to dissected, mostly j^etioled : flowers somewhat inclined to 

 polj'gamo-dicecious through abortion of the ovaries ; annual herbs. — Cyclacliana, 

 Fresen. lud. Sem. Hort. Franc. 1836, & Linn. xii. ; Torr. & Grav. 1. c. 285. 



