COMPOSURE. 313 



Very anomalous specimens occur occasionally, especially among the 

 Plume Thistles, which are generally believed to be natural hybrids. 



1. Milk Thistle. Carduus IVIariaiius, Linn. 

 (Eng. Bot. t. 976. Sill/bum, Bab. Man.) 



An annual or biennial, 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, sohtary at the ends of the 

 branches, with purple florets. Bracts of tlie involucre very broad at the 

 base, with a stiff, spreading, leafy appendage, ending in a long prickle, and 

 bordered with prickles at its base. Hairs of the pappus simple. 



In waste places, in southern Europe to the Caucasnis ; not indigenous in 

 central Europe, although it occurs here and there as a weed of cultivation. 

 Rare and probably only introduced into Britain. Fl. summer. 



2. Musk Thistle. Carduus nutans, Linn. 

 (Eng. Bot. t. 1112.) 



A stout species, 2 to 3 feet high, usually slightly covered mth loose cot- 

 tony hairs. Leaves deeply pinnatifid, very prickly, their edges decurrent 

 along the stem, forming narrow very prickly wings. Flower-heads large 

 and drooping, as in the milk T., but often 3 or 4 in a loose corymb. In- 

 volucral bracts numerous, with a stiS", 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 south- 

 ern England, especially on limestone soUs, less so in the north, and rare in 

 Scotland. Occurs also in Ireland. Fl. summer. 



3. V^elted Thistle. Carduus acanthoides, Linn. 

 (Eng. Bot. t. 973.) 



Much resembles the musk T., but is usually taller and rather more 

 branched ; the leaves narrower and more prickly ; and the stem more tluckly 

 covered with prickly appendages, decurrent from the base of the leaves. 

 Flower-heads not so large, though yet globular and shghtly drooping ; the 

 involucral bracts very numerous and narrow, ending in a hnear, spreading 

 or recurved prickle, the innermost often of a thinner texture, shghtly coloured 

 and scarcely prickly. Hairs of the pappus simple. 



A very common Continental Thistle, extending eastward entirely across 

 Asia, and northward to the Arctic Circle, although in Britain, Uke many 

 others, it becomes scarce in Scotland. Fl. summer. Two forms are often 

 distinguished as species, the C. acantlioides, with the flower-heads single, on 

 long peduncles, and the leaves often nearly glabrous, and C. crKpus, with 

 the heads clustered several together on short stalks, and the leaves usually 

 rather broader and more cottony underneath; but they run too much one 

 into the other to be separable even as permanent varieties. 



4. Slender Thistle. Carduus pycnocephalus, Jacq. 

 (C. tenuiflorus, Eng. Bot. t. 412.) 

 A stifi" annual or biennial, from 1 to 3 or 4 feet high, but not so stout 

 as the three last, and much more covered, especially the stems and the under 



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