ORDER 10. COMPOSITE. 467 



hairy; pappus in 3 series, the outer 10-toothed, the 2 inner each 



10-bristled. Oriental herbs. 



C. benedictus L. Lvs. somewhat decurrent ; dentate and spiny; invol. doubly 

 spinous, woolly, bracteate. OD Native of Persia, Tauria and Greece. About 2f 

 high, with yellow flowers. Sparingly naturalized. June. It was formerly in 

 great estimation in medicine, but is now considered worthless. \ 



95. ONOPOR'DON, Vaill. COTTON THISTLE. Heads discoid, homo- 

 gamous ; involucre ventricous, imbricate with spreading, spinous scales ; 

 receptacle deeply alveolate ; pappus copious, capillary, scabrous ; ache- 

 nia 4-angled. Large, branching herbs, with decurrent leaves. 



O. acanthium L. Invol. scales spreading, subulate ; Ivs. ovate-oblong, decurrent, 

 sinuate, spinous, woolly on both sides. (g) This fine looking thistle occurs natur- 

 alized in waste grounds, and is about 3f in height. The whole plant has a white, 

 cottony appearance. Stem winged by the decurrent leaves, which are unusually 

 large. Involucre round, cottony, spinous. Flowers purple. July, Aug. Eur. 



96. CIR'SIUM, Tourn. (Cnicus L. Muhl.) THISTLE. (Gr. Kipooc, 

 a swelling of a vein, which this plant was supposed to heal.) Heads 

 discoid, homogamous ; involucre subglobous, of many rows of spi- 

 nous-pointed, imbricated scales ; receptacle bristly ; style scarcely 

 divided ; pappus copious, plumous ; achenia compressed, smooth. 

 Herbs with alternate Ivs., generally armed with spinous prickles. Fls. 

 cyanic. 



* Leaves decurrent,on the stem more or less. Scales tipped with spines Nos. 1, 2 



* Leaves not decurrent. Heads involucrate with a whorl of 12 to 20 spiny bracts No. 3 



Heads naked. Flowers ochroleucous. Scales prickly No. 4 



Fls. purple. Lvs. vvhite-tomentous beneath. .Nos. 5 7 



Lvs. green. Stem low, simple.. Nos. 8, 9 



Stem tall, branched. .No. 10 



1 C. lanceolatum Scop. COMMON THISTLE. Lvs. decurrent, pinnatifid, hispid, 

 the segments divaricate and spinous; fids, several, ovoid, vittous; scales lanceolate, 

 tipped with a spine, spreading. (2) Common in borders of fields, roadsides, N. 

 Eng. and Mid. States, always distinguished by the decurrent leaves. St. 3 to 4f 

 high, winged by the decurrent leaves which are white and woolly beneath, 

 armed with formidable spines at all points. Fls. numerous, large, purple. Invol. 

 scales, webbed, each ending in a spine. Jl. Sept. 



2 C. Lecontii Torr. & Gr. Slender, simple, with one head] Ivs. linear-lanceolate, 

 more or less decurrent, with a few spinous teeth, glabrous above, \vhite-floccous 

 beneath, invol. ovoid, arachnoid when young; scaks not spinous, merely mucro- 

 nate or acuminate-pointed. Ga. to La. St. about 2f high. Hd. large, (I 1 or 

 more diam.) terminal. 



3 C. horridulum Ms. Lvs. sessile, pinnatifid, acutely cut, spinous ; hds, invested 

 with an external invol. of about 12 to 20 very spinous bracts; scales sharp-pointed, 

 but unarmed. (9) Found in meadows and hills, N. Eng. to Fla. St. 1 to 3f high, 

 invested with wool. Lvs. somewhat clasping, woolly and hairy, armed with stiff 

 spines. Hds. largo (!' diam.), with yellowish white corollas, the scales webbed. 

 Aug. 



(3. ELLIOTTII. Corollas purple, 2' long. Bracts about 12. South (Elliott). Fla., 

 near Quincy. 



4 C. Pftcheri, Torr. & Gr. White-tomentous ; Ivs. rigid, pinnately parted, mar- 

 gins revolute, segm. long, linear, toothed or entire, spinous ; hds. axillary ; scales 

 arachnoid, acuminate, tipped with a weak, spreading prickle. Sandy lake shoresj 

 Mich, and Can. "West. Cor. ochroleucous. Jn., Jl. 



5 C. discolor Spreng. Lvs. sessile, pinnatifid, rough-haired, downy beneath, 

 segm. 2-lobed, divaricate, spinous; invol. globous, the scales ovate, appressed. 

 with spreading spines at the tip. A slender thistle 3 to 5f high, much branch- 

 ed and leafy at the summit, found in thickets. N. Eng. to III Hds. terminating 

 the branches, 1' diam., with reddish purple corollas. Jl. Aug. 



