468 Obdee to.— composite. 



6 C. altissimuni'Spreng. Tall, branched, villous-pubescent, kafy ioihe top; his. 

 whitish beneath, spinous-oiliate, sessile, lanceolate oblong, often sinuate-dentate, loiuer 

 imdimded or pinnatifid petiolate, lobes or teeth spinesoent. Hds. large, scales 

 ovate-lanoeolate, outer one with a spreading spine at apex. — Fields and barrens, 

 Penn. and W. States, common. St. 3 to 8f high. Lvs. 6 to 8', by 1 to 6'. Hds. 

 about 1' diam., with linear-lanceolate bracts at base. M. purple or purplish 

 white. Aug. 



7 C. ViTginianum Michx. Slfender, mostly simple, and naked above; lvs. 

 sessile, lanceolate, margin reuolute, entire or repand-dentate, teeth spinescent, or 

 sometimes remotely sinuate-lobed or pinnatifid, upper surface glabrous, under 

 surface tomentous-oanescent ; hds. smail; invol. subglobous ; scales tipped with a 

 short, spreading prickle. — "Woods, Ohio, and S. States. Plant about the size of the 

 Canada thistle, clothed with an arachnoid pubescence, with few or many heads 

 (sometimes but one) which are about f diam. Flowers purple. Apr. — Sept. 

 (Carduus, L. Cuious, Ph.) 



8 C repdndum Mx. Arachnoid when young ; lvs. crowded to the top, at length 

 green both sides, clasping oilong-Unear, undidate, spinous-ciliale ; hds. 1 or 2; 

 scales, outer ovate-lanceolate, inner subulate-acuminate. — Barrens, N. Car. to Ga. 



9 C. ptimilum Spreng. Hairy; lvs. few above, green on both sides, clasping, 

 oblong-lanceolate, pinnatifid, the segm. irregularly lobed, ciliate, spinous ; ?uls. few, 

 very large, subtended by 1 to 5 bracts ; invol. round-ovate, spinous. — @ A common, 

 low, turgid thistle, in roadsides, pastures, N. Eng. and Mid. States. St. 1 to 2f 

 high, stout, striate, with 1 to 3 very largo heads of fragrant, purple fls. Aug. 

 (Cnious odoratus Muhl.) 



10 C. mfiticum Mx. Lvs. pinnatifid with divaricate segments ; hds. on 

 naked peduncles without bracts; invol. ovoid with unarmed, villous-arachnoid, 

 glutinous scales. — @ A. fine looking thistle found in damp soils. Can. and U. S. 

 St. branching, 3 to Tf liigh. Lvs. armed with spines at each angle. Hds. 1' diam., 

 with deep purple corollas, the scales webbed and glutinous on the back. Aug., 

 Sept. 



11 C. glaber Nutt. Tall, slender, nearly glabrous ; lvs. lance-linear, rigid, with 

 spinescent, divaricate segments, the lower slightly decurrent; hds. naked, on, leafliss 

 stalks; scales seiaceously mucronate, strongly keeled, almost glabrous, the inner 

 attenuate-acuminate. — N". Jer. to Ga. St. very smooth, angled, 3 to 5f high. Lvs. 

 minutely arachnoid beneath. Hds. 6" diam., truncate at base. Fls. purple. Jl. 

 Sept. 



12 C. arvense Scop. Canada. Thistle, CtJESED Thistle. Lvs. sessile, sinua,te- 

 pinnatifid, wavy, spinous; st. panioled; hds. nvmierous, small, invol. round or 

 ovate, with minute spines, scales dose-pressed, ovate-lanceolate. — y Common in 

 fields, roadsides and waste places, N. Eng. to 'W. States, very troublesome to the 

 farmer. Root creeping, long and tenacious of life. St. 3f high, with a branching 

 panicle at top. Hds. small (4 to 5" diam.) purple, the involucre nearly thomless, 

 and is the only part of the plant that can be safely handled. Jl. § Eur. 



97. LAP'PA, Tourn. Burdock. (Lat. lappa, a burr, from Gr. Xa(ieTv, 

 to lay hold of; a characteristic term.) Heads discoid, homogamous; invo- 

 lucre globons, the scales imbricated and hooked at the extremity ; re- 

 ceptacle bristly ; pappus bristly, scabrous, caducous. — ® Coarse, Euro- 

 pean herbs. Lvs. alternate, large. 



Ii. major Gaert. Lvs. cordate, unarmed, petioled. — Common in waste and culti- 

 vated grounds, fields. N. Eng., Mid. and W. States. , Each plant is a large, coni- 

 cal, iU-soented and coarse-looking mass of vegetation, surmounted by a branching, 

 irregular panicle of ovoid heads with tubular corollas of an exceedingly delicate 

 pink color. The leaves are very large, with wavy edges. It has a wonderful de-. 

 sign for the dispersion of its seeds. The scales of the involucre all end in a mi- 

 nute, firm hook, which seizes hold of everything that passes by. Jl, Aug. § Eur. 

 (Arctium Lappa L.) 

 /?. Leaves plnnaMd.-^-Penn. (Darlington). 



