468 ORDER 70. COMPOSITE. 



6 C. altissimum Spreng. Tall, branched, villous-pubcscent, leafy to the top ; Ivs, 

 whitish beneath, spinous-ciliate, sessile, lanceolate oblong, often sinuate-dentate, lower 

 undivided or pinnatifid petiolate. lobes or teeth spinescent. Hds. large, scales 

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

 Perm, 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. Fl. purple or purplish 

 white. Aug. 



7 C. Virginianum Michx. Slender, mostly simple, and naked above; Ivs. 

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

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

 surface tomentous-canescent ; hds. small; 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 ' diam. Flowers purple. Apr. Sept. 

 (Carduus, L. Cnicus, Ph.) 



8 C. repandum MX. Arachnoid when young ; Ivs. crowded to the top, at length 

 green both sides, clasping oblong-linear, undulate, spinous-ciliate; hds. 1 or 2; 

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



9 C. pumilum Spreng. Hairy; Ivs. few above, green on both sides, clasping, 

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

 very large, subtended by I to 5 bracts ; invol. round-ovate, spinous. (D 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 large heads of fragrant, purple fls. Aug. 

 (Cnicus odoratus Muhl.) 



10 C. muticum 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 If high. 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; Ivs. lance-linear, rigid, with 

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

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

 attenuate-acuminate. 1ST. Jer. to Ga. St. very smooth, angled, 3 to 5f high. Lvs. 

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

 Sept. 



12 C. arvense Scop. CANADA. THISTLE, CURSED THISTLE. Lvs. sessile, sinuate- 

 pinnatifid, wavy, spinous ; st. . panicled ; hds. numerous, small, invol. round or 

 ovate, with minute spines, scales close-pressed, ovate-lanceolate. It Common in 

 fields, roadsides and waste places, N. Eng. to TV. 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 thornless, 

 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. 

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

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

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

 pean herbs. Lvs. alternate, large. 



L. 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, ill-scented 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.) 



8. Leaves pinnatifid. Penn. (Darlington). 



