180 WEEDS AND USEFUL PLANTS. 



3-lobed, armed at base with slender 3-parted spines ; involucre of the 

 fruit cylindric-oblong, with an inconspicuous beak. 

 SPINOSE XANTHIUM. Thorny Clot-bur. 



Stem 2-3 or 4 feet high, branched. Leaves 1 - 3 inches long, and one-fourth to three- 

 fourths of an inch wide, entire or with a lobe-like tooth on each side, the upper surface 

 pale green, pubescent on the midrib the under surface clothed with a short cinereous 

 tomentum, the base narrowed to a short petiole on each side of which is a triple or 

 3-forked spine, the branches about an inch long, very sharp, yellowish or pale straw color. 

 Heads of flowers axillary, solitary. 



Farm-yards, road-sides, &c. : Massachusetts to Georgia : introduced. Native of Eu- 

 rope. Fl. September. Fr. October. 



Obs. This execrable weed, believed to have originated in tropical 

 America, and now widely diffused through various parts of the old 

 world, is becoming naturalized in many portions of our country, par- 

 ticularly in the Southern States. It may be frequently seen along the 

 side-walks, and waste places, in the suburbs of our northern sea-port 

 towns, and is a vile nuisance wherever found. I have understood that 

 the authorities of one of our cities, a few years since, enacted an Ordi- 

 nance against the plant, in which enactment it was denounced by the 

 name of the Canada Thistle ! The misnomer probably did not impair 

 the efficacy of the Ordinance : yet I cannot help thinking it would be 

 decidedly preferable that both lawgivers and farmers should avoid 

 confounding objects which are essentially distinct, and learn to desig- 

 nate even weeds by their proper names. 



10. RUDBEC'KIA, L. CONE-FLOWER. 



[In honor of Olaus Rudlxck, father and son ; Sweedish botanists.] 



Heads many-flowered ; ray-florets neutral. Involucral scales in about 2 

 series, leaf-like, spreading. Receptacle more or less columnar ; chaff short, 

 conical, not rigid. Akenes 4-angled, smooth ; pappus a minute crown- 

 like border. Chiefly perennials ; leaves alternate ; rays yellow, generally 

 long and drooping. 



1. R. hir'ta, Hirsute ; lower leaves spatulate, petiolate, upper ones 

 ovate-lanceolate, sessile ; disk conical, dark purple. 



ROUGH-HAIRED RUDBECKIA. 



Perennial? Stem 1^-4 feet high, rather stout, often simple or branched near the 

 base. Leaves 2 -3 inches long, the radical ones on hirsute petioles 1-2 inches in length. 

 Heads of flowers middle-sized, on long stoutish striate sulcate naked peduncles ; chaff of 

 the receptacle sublinear, rather acute, hairy and ciliate at the summit. 



Fields and in dry soil. July - September. 



Obs. This is of late becoming rather common in cultivated lands, and 

 cannot fail to attract the notice of the farmer. Another species which 

 nearly resembles it, R, ful'gida, Ait., is also found in similar situations ; 

 the latter has 3-nerved leaves, and smooth chaff to the receptacle. But 

 little is known of their character as weeds, but they have apparently an 

 encroaching disposition, and should be eradicated. 



