COMPOSITE. (COMPOSITE FAMILY.) 233 



Herbs, with sessile, alternate leaves, often pinnatifid, and prickly. Heads large, 

 terminal. Flowers reddish-purple or cream-color. (Name from Kipcros, a sicclled 

 vein, for which the Thistle was a reputed remedy.) 



* Scales of the involucre all tipped with spreading prickles. 



1. C. LAXcEOL.Vru-M, Scop. (Common Thistle.) Leaves decurrent on 

 the stem, forming prickly lobed wings, pinnatifid, rough and bristly above, 

 woolly with decidous webby hairs beneath, prickly ; flowers purple, (2") — Pas- 

 tures and road-sides, everywhere, at the North. (Nat. from En.) 



# # Scales of the involucre appressed ; the inner ones not prickly : filaments hairy. 



-t- Leaves white-woolly beneath, and sometimes also above : outer satlts of the involucre 



successively shorter, and tipped with short prickles. 



2. C. Pitclieri, Ton-. & Gr. White-woolly throughout, low; stem stout, 

 Terr leafy ; leaves all pinnately parted into rigid narroicly limar and elongated divis- 

 ions, with revolute margins ; flowers cream-color. 1J. — Sandy shores of Lakes 

 Michigan, Huron, and Superior. 



3. C. Uiullllittlllll, Spreng. White-woolly throughout, low and stout, 

 leafy ; leaves lanceolate-oblong, partly clasping, undulate-pimiatijul, with prickly 

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

 thence westward. July. 



4. C discolor, Spreng. Stem grooved, hair}-, branched, leafy; leai<es 

 all deeply pinnatifid, sparingly hairy and green above, whitened with close wool l>e- 

 neath ; the diverging lobes 2 - 3-rl/ft, linear-lanceolate, prickly-pointed ; flowers pale 

 purple. (|) — Meadows and copses; not uncommon. Aug. — Plant 3° -6° 

 high : heads 1' or more in width. 



5. C. aHissiaaiiiin, Spreng. Stem downy, branching, leafy to the heads: 

 leaves roughish-hairy above, whitened with close wool beneath, oblong-lanceolate, 

 sinuate-toothed, undulate-pinnatijid, or undivided, the lobes or teeth prickly, those 

 from the base pinnatifid; lobes short, A'ong or triangular ; flowers chiefly purple, 



lj.? — Fields and copses, Penn. to Ohio, Illinois, and southward. Aug. — 

 Plant 3° -10° high: leaves variable: the heads much as in the last. 



0. C. Vii'giiiiiiuum, Michx. Stem woolly, slender, simple or sparingly 



branched, the branches or long peduncles naked; leaves •, green above, 



whitened with close wool beneath, ciliate with prickly bristles, entire or sparingly 

 sinuate-lobcd, sometimes the lower deeply sinuate-pinnatifid ; outer scales of the 

 involucre scarcely prickly; flowers purple. — Woods ami plains, Virginia, Ohio, 

 and southward. July. — Plant 1°- 3° high; the heads seldom more than half 

 as large as in the last. 



Var. filifH'iailuIum. Stem stouter, more leafy, corymbosely branched 

 above; the heads on shorter peduncles; leaves pinnatifid; roots tuberous, en- 

 larged below. (C. filipendulum, Engelm.) — Illinois and southwestward. 



*- •*- Leaves green both sides, or only ivith loose webby hairs underneath : scales of the 

 involucre scarcely prickly-pointed. 



7. C. muticuni, Michx. (Swamp Thistle.) Stem tall (3°-3° high), 

 angled, smoothish, panicled at the summit, the branches sparingly leafy and 

 bearing single or few rather large naked heads; leaves somewhat ha ; ry above, 



20* 



