196 



AVEEDS AXD USEFUL PLANTS. 



Root biennial. Stem 2-4 feet high, branched, striate-sulcate, hairy, winged by the de- 

 current leaves. i€ares4-8 or 12 inches long. Heads terminal, erect, about an inch in 

 diameter ; scales of the involucre connected by a cobweb-like villus. I lorets purple, with 

 yellowish anthers. Akenes small, obovate-oblong ; pappus about an inch long, sillcy. 



Pastures, fence-rows, way-sides, kc. : Xorthcru and Middle States : introduced. Xativo 

 of Europe. J'L June -July. J^r. July -August. 



Ohs. This foreigner, wliicb deliglits in a ricli soil, is abundantly nat- 

 uralized in the Northern States, generally. Though not so repulsive 

 and ugly as some others of the spiuose Compositee, it is nevertheless a 

 very objectionable weed on the farm, and requires constant vigilance and 

 attention to exclude it, or keep it in subjection. If permitted to mature 

 its fruit, the spreading pappus may be seen, by hundreds, floating the 

 akenes through the air, and disseminating the noxious intruder far and 

 wide. 



Scales of the involucre appressed ; the inner ones not pricJcly : filaments 

 hairy. 



f Leaves white, woolly beneath. 



2. C. dis 'color, Spreng. Leaves deeply pinnatifid, sparsely hairy and 

 green above, densely hoary-tomentose beneath — the segments linear- 

 lanceolate, cuspidate and spinulose-ciliate ; involucre ovoid-oblong ; 

 scales appressed, tipped with a slender prickle — the outer or lower scales 

 lance-ovate, the inner or upper ones linear-lanceolate. 



Two-colored Ciesium. 



Root biennial. Stem 2-5 feet high, with rather slender spreading leafy branches, 

 striate, pubescent with crisped membranous hairs, iearas 3 or 4-12 or 15 inches long 

 (those on the branches small), the under surface bluish-white with a soft dense tomen- 

 tum. Heads 1-2 inches long, and an inch or more in diameter ; scales somewhat arach- 

 noid-villous. Florets reddish-purple, with whitish anthers. 



Fields and borders of thickets : Northern and Western States. I'l. Aug. -Sept. Fi: 

 Sept. -October. 



Obs. Like all others of the genus, this is a worthless, obnoxious weed, 

 but is much easier kept in subjection than the preceding. 



ff Leaves green on both sides, or with loose ivooll y hairs beneath ; scales of 

 the involucre scarcely prickly pointed. 



3. C. pu'miium, Spreng. Leaves semi-amplexicaul, pinnatifid, green 

 on both sides — the segments short, irregularly lobed, spinulose-ciliate and 

 pointed with strong sharp spines ; heads few and large, roundish-ovoid, 

 bracteate ; scales of the involucre appressed — the outer ones ovate- 

 lanceolate, acuminate, tipped with a short spine, the inner ones lance- 

 linear with acuminate scarious serrulate tips. 



Low OR Dwarf Cirsium. Pasture Thistle. 



Plard pale grej^ish green. Root biennial. Stem 1-2 feet high, stout, sparingly branched, 

 striate, rctrorsely pilose. Leaxes 4-12 inches long, very prickh", more or less hairy, 

 densely pilose on the midrib beneath. Heads few (1-3), often near 2 inches in diameter, 

 mostly with large pinnatitid spinose bracts at base. Florets often 2 inches in length, 

 usually of a pale reddish-purple, with whitish anthers. 



Neglected old fields and low grounds : iiiddle and Northern States. Fl. July. Ff 

 August. 



