COMPOSIT.E. (COMPOSITK IWIMILV.) 273 



67. CIRSIUM, Tonm. Common- or ri.rMr.n TniSTi.E. 



Heads maiiy-llowcrnl ; the Ilowcrs all tuhuhir, perfect and similar, or rarely 

 imperfeetiv dlteeioiis. Scales of the ovoid or sjilierieal involucre imbricated in 

 many rows, tipped witli ajwint or prickle. IJeceptaele thickly clothed with soft 

 hristles or hairs. Aehenia ohlon;,', (lattish, not ribbed. Pappus of numerous 

 bristles united into a rinj^at the base, plumose to the middle, deciduous. — Herbs, 

 with sessile alternate leaves, often pinnatilid, and priekl}'. Heads large, ter- 

 minal. Flowers reddish-purple, occasionally yenowisii, white, or cream-color; 

 in summer. (Name I'nnn Kipdos, a mnllid vein, i'ov which the Thistle was a 

 reputed remedy.) 



♦ Scales of the involucre all tipped ivith spreading prickles: root biennial. 



1. C. l.a^nceol.Vtum, Seop (Co.mmon Thistle.) Leaves deeurrcnt on 

 the stem, forming prickly lobed wings, ])innatitid, rough and bristly above, 

 Moolly with deciduous webby hairs beneath, prickly ; flowers purple. — Pastures 

 and roadsides, everywhere, at the North. (Nat. from Eu.) 



♦ « Scales of the involucre a})prrssed ; the inner ones not pricLlij : f laments hain/. 



t- Leaves white-ivoollij beneath, and sometimes also above: outer scales of the involucre 



successiveli/ shorter, and tipped with short prickles. 



2. C. Pitcheri, Torr. & Gr. Wlute-ivoollij throughout, perennial, low ; stem 

 stout, very leafv ; leaves all pinnateli/ parted into rigid narrowly linear and elongated 

 divisions, with rcvolute margins; flowers cream-color. — Sandy shores of Lakes 

 Michigan, Huron, and Siijicrior. 



3. C. Undul^tum, Spreng. White-woollg throughout, biennial, low and 

 stout, leafy; haves luuceolate-ohlong, partly ela-ping, undulate-pi nnali fid, with 

 prickly lobes; flowers reddish-purple. — Islands of L. Huron and Michigan; 

 thence westward. 



4. C. discolor, Spreng. Biennial ; stem grooved, hairy, liranched, tall, 

 leafj'; leaves all deeply pinnatijid, sparingly hairy and green above, tvhilcned with 

 close wool beneath ; the diverging lobes 2-3-cleft, linear-lanceolate, prickly-pointe'l ; 



cpiile to the heads: haves roughish-hairy aliovc, whitened with close wool l)eneath, ' . y^ 

 oblong-lanceolate sinuate-toothed, undulate-pinnafi'fid, or undivided, the lobes or teeth r 

 jjrickly ; those from the base pinnatifid ; and their Wjcs short, oblong or triangular : 

 flowers chiefly i)uriile. — Fields and copses, Penn. to Illinois and southward. 



G. C. Virginiknum, Miehx. Stem woolly, slender. sim])le or sparingly 

 i)ranchcd (l°-3° high) ; the bra'iches or long jmlnncles naked: leaves lanceolate, 

 green above, whitened with close wool beneath, ciliate with prickly bristles, en- 

 tire or sparingig sinuatel(J>ed, sometimes the lower dee])ly sinuate-pinnatifld ; outei 

 scales of the involucre scarcely prickly; heads small; flowers purj)le. — Wood* 

 and plains, Virginia, Ohio, and southward. 



Var. fllip6ndulum. Stem stouter, more leafy, corymboscly branched 

 above; the brads on shorter peduncles; leaves iiinnatifld : roots tuberous, en- 

 larged below. (C. lilipeiidulum, Kugelm.) — I'rairies of S. Illinois and south- 

 westward. 



18 



flowers pale jturple, rarely white. — Meadows and copses. 



C. altissimum, Spreng. Stem downy, branching (.3°- lOOhi-lO.^/y a 



