C. lanceolatum (L.) Hill. Bull Thistle. —p A stout weed 
1-1.5 m. tall, the stems very leafy more or less woolly, bran cc 
leaves green, strongly undulate, lanceolate or narrowly ovate, 6-20 om. long 
or more, deeply pinnatifid into lanceolate or oblon ~lanceolate lobes 5-6 | 
long, ev—ta—tha_sualler leaves into daltoid Tebse> all tipped with ait: be 
as much as 1 cm. or more long, the upper surface ve harsh with stirr a 
8 
hairs, the lower cobwebby or woolly, the margins « Teowes 
most 
smooth, all decurrent upon the stems, forming spinose herbaceous wings; ney 
few, 4-6 cme in diameter, crowded, the involucral bracts linear, the foie 
5 cme long, all tipped with a short Spine, thinly cobwebby, spreading above 
the middle; flowers rose-purple 4 cm. long, the corolla lobes linear, 7 mm. long: 
achenes 4 mm. long, the pappus 3-4 cm. long. . 83 
Common in waste places, along roads and in denuded burns; 
introd 
Europe. uged from 
Cr C. arvense (L.) Scop. Canadian Thistle. ——-> A perennial herb with 
matted creeping rootstocks, the slender stems thus gregarious, 1-2 m. tall, 
glabrous, much branched in the upper parts p-bhe—branctres—escendiny: leaves 
green, mostly oblong-lanceolate, 5-15 cm. long or more, pinnatifid, their : 
segnents irregularly deltoid, «5-2 cm. long, the margins Spinose with numerous 
prickles 5-6 mm. long, undulate, glabrous or sparingly cobwebby beneath, sessile 
and somewhat clasping at the base; heads numerous, 15-20 mn. tall, 10-15 mm. 
; ~~ , +o—Or—orre—svenchesy dioecious, the staminate 
heads subglobose, the flowers much exserted, the pistillate Ccampanulate, the 
flowers hardly exserted; bracts of the involucre glabrate, purplish, the outer 
ovate, 5-5 mm. long, the inner narrowly lanceolate, all acuminate, glabrate, the 
tips somewhat cobwebby and ciliate, the outermost recurving, soft, not Spinose, 
each with a dorsal glutinous ridge; flowers lavender, 1.5 om. long, the corolla 
lobes 5 mme long; achenes 2-65 mm. long, the pappus 1-2 cm. long. 
aabe! Gane - i OO yes rr |) > a oe Vo 
A frequent and pernicious weed in waste places at low elevations; intro- 
duced from Rkurope. . 
sa apdbliais Pe 
amet Ce undulatum (Nutt.) Spreng. —_-______-> Stems erect, branching, the branches 
rather slender, densely and_ persistently white-tomentose; leaves mostly lanceo- 
late in outline, the lowermost broadly so or oblanceolate, the blades of the 
lower 15-30 cm. long, borne on petioles half as long, the upper 8-15 cm. long, bo, 
sessile and clasping, all pinnately lobed, the lobes of the lower oblong in 
outline, 4-5 cm. long, again incised with 2 or 3 salient lobes, those of the 
upper leaves mostly deltoid, all armed with sharp Spines 2-4 mm. long, the 
margins armed with smaller prickles, the upper surfaces cobwebby, frequently 
becoming glabrate and ashy, the lower surfaces densely and persistently white@ =/ 
tomentose; heads borne at the tips of the branches, not at all crowded, 15-20 
mm. broad, their involucral bracts lanceolate, the inner 20-25 mm. long, all 
sparingly cobwebby, nearly glabrous, bearing & glandular ridge 2-3 mm. long near 
y the apex, the tips spinose, spreading; flowers pink or whitish- 
Frequent along roadways in the srassland and at lower elevations. 
