ORDER LXVTII. COMPOSITJ5. 405 



bristly. Florets of the ray pistillate, funnel-shaped, irregular ; 

 those of the disk staminate. Pappus consisting of three series, 

 the exterior a toothed margin, the middle one composed of 10 

 or 12 awns, the interior one short, hairy. 



1. C. America'na, (Nutt.) Stem erect, striate, somewhat branched. 

 Leaven glabrous, sessile, oblong-ovate, repand toothed, the upper lance- 

 olate ; scales of the involucre with pectinate appendages. Heads large, 

 showy. — Pale purple. Cultivated. Louisiana, Texas. 2 — 3 feet. 



Genus LXXX.— CNI'CUS. VailL 

 (From knizo, to prick.) 



Heads many-flowered ; florets of the disk and ray similar. 

 Scales of the involucre coriaceous, produced into long, hard, 

 spiny, pinnate appendages. Receptacle flat, covered with capil- 

 lary bristles. Achenia longitudinally striate. Pappus triple. 



1. C. benedjc'tus. Stem villous, branching. Leaves subpinnatifid, 

 clasping, decurrent. Flowers yellow. — 0. Louisiana. 



Genus LXXXL— CIR'SIUM. Tourn. (Cnicus.) 

 (From Hrsos, a swelled vein, for which the thistle was supposed to be a remedy.) 



Involucre ventricose, imbricate, with spinose scales. Florets 

 perfect. Receptacle hairy. Pappus plumose, or pilose. 



1. C. disco'lor, (Spren.) Stem erect, hairy. Leaves sessile, pinnati- 

 fid ; segments 2-lobed, spinous, hairy on the upper surface, tomentose 

 beneath. Flowers solitary, terminal, on leafy branches; scales of the 

 involucre ovate, terminated by a long spine. Seed smooth ; pappus 

 plumose. — Purple. If. June — July. Upper dist. Car. and Geo. 



2. C. altis'simum, (Spren.) Stem erect, branching. Leaves sessile, 

 oblong-lanceolate, scabious, tomentose beneath, dentate, ciliate, radical 

 ones pinnatifid. Flowers terminal ; involucre cylindrical, ovate ; scales 

 ovate, spinoxis, appressed, pale ; receptacle villous. — Purple. If. July 

 — Sept. Upper dist. Car. and Geo. 2 — 3 feet. 



3 C. Virginia'num, (Mich.) Stem simple, angled, tomentose toward 

 the summit. Leaves sessile, narrow-lanceolate, with spiny teeth, acute, 

 slightly hairy on the upper surface, tomentose beneath. Flowers soli- 

 tary, terminal ; involucre ventricose ; scales appressed, carinate, ovate. 

 Seeds slightly angled, oblong; pappus plumose; receptacle bristly. — 

 Purple. If. June — Sept. Pine-barrens. Common. 2 — 3 feet. 



4. C. mu'ticum, (Mich.) Stem erect, slender, branching. Leaves pin- 

 natifid, woolly, tomentose beneath ; segments with spines, somewhat 

 bracteolate, occasionally 3-lobed, pale, acute ; branches naked, 1-flow- 

 ered ; involucre globose; scales without spines, lanuginous. — Purple. 

 If July — Sept. Mountains. 2 — 6 feet. Cnicus muticus, Pursh. 



5. C. gla'ber. (C. muticum, Mich.) Stem erect, furrowed, sprinkled 

 with hairs, branching. Leaves sessile, pinnatifid, very long, hairy along the 

 veins, spiny along the margins and angles ; segments 3 — 5-lobed. Flow- 

 «rs in panicles. Peduncles slender, slightly hairy ; scales of the involu- 



