Carduus. | XLII COMPOSITA. 251 
Bracts of the involucre lanceolate or linear, without lateral 
prickles. Involucres globular, large. 
Involucral bracts broadly lanceolate . ‘ } . 2. C. nutans, 
Involucral bracts linear . ? ‘ ; , P . 38. C. acanthoides. 
Involucres ovoid or cylindrical . ‘ , . 4 C. pycnocephalus. 
Pappus consisting of feathery hairs (Crrous). 
Leaves decurrent along the stem, forming prickly wings. 
Flower-heads all peduncled. 
Flower-heads few, near 14 inches long. Stem winged 
and prickly. Root biennial . . 5. C. lanceolatus. 
Flower-heads not an inch long, in terminal ‘corymbs. 
Leaves but little decurrent. Rootstock creeping . 7. C. arvensis. 
Flower-heads pee in dente UTBREEEE Stem winged and 
prickly, . . : . 6. C. palustris. 
Leaves not decurrent, or only very shortly y $0. 
Flower-heads sessile or on very short peduncles. 
Stems} stout and branched Ghent 2 feet). Involucres 
large and cottony. ‘ . 8. C. eriophorus. 
Stems dwarf, or scarcely any.  Involucres not cottony. 12. C. acaulis, 
Flower-heads all peduncled. Rootstock perennial, often 
creeping. 
Flower-heads in terminal corymbs . ‘ . 7. C. arvensis. 
Flower-heads growing singly, on long peduncles. 
Leaves ciliate, not prickly, very white underneath . 9, C. heterophyllus. 
Leaves prickly, green, or with a loose white cotton 
underneath. 
Leaves deeply pinnatifid and lobed. Flower-heads 
usually 2 to 4 10. C, tuberosus. 
Leaves toothed, sinuate, or shortly lobed. Flower- 
heads usually solitary or 2 only 4 ‘ ll. C. pratensis. 
Very anomalous specimens occur occasionally, especially among the 
Cnicuses, which are generally believed to be natural hybrids. 
1, ©. Marianus, Linn. (fig. 556). Milk Thistle.—An annual or bien- 
nial, 2 to 3 feet high, not much branched, and glabrous or with but very 
little cottony wool. Leaves smooth and shining above, and variegated by 
white veins ; the lower ones deeply pinnatifid with broad very prickly lobes ; 
the upper ones clasping the stem by prickly auricles but scarcely decurrent. 
Flower-heads large, drooping, solitary at the ends of the branches, with 
purple florets. Bracts of the involucre very broad at the base, with a stiff, 
spreading, leafy appendage, ending in a long prickle, and bordered with 
prickles at the base. Hairs of the pappus simple, Stlybum Marianum, 
Gertn. 
In waste places, in southern Europe to the Caucasus ; not indigenous in 
central Europe, although it occurs here and there as a weed of cultivation. 
Rare and only introduced into Britain, #7. summer. 
2. ©. nutans, Linn. (fig. 557). Musk Thistle.—A stout species, 2 to 
3 feet high, usually slightly covered with loose cottony hairs. Leaves 
deeply pinnatifid, very prickly, their edges decurrent along the stem, 
forming narrow very prickly wings. Flower-heads large and drooping, as 
in C. Marianus, but often 3 or 4 ina loose corymb. Involucral bracts 
numerous, with a stiff, narrow-lanceolate appendage, ending in a spreading 
or reflexed prickle, but without lateral prickles. Hairs of the pappus 
simple. 
In waste places, common in the greater part of Europe and temperate 
Asia, but not spreading to the extreme north. Pretty frequent in southern 
England, especially on limestone soils, less so in the north, and rare in 
Scotland. Occurs also in Ireland. FV. summer. 
