254 THE COMPOSITE FAMILY. 



star. Keceptacle bearing irregularly cut, chaffy scales between the 

 florets. Achenes silky-hairy, with a feathery pappus. 



A small European and Asiatic genus, easily distinguished by the in- 

 NV volucral bracts. 



1. C. vulgaris, Linn. (fig. 571). Common C. An erect biennial, 

 seldom above 6 or 8 inches high. Leaves not decurrent, toothed, or 

 pinnatifid, and very prickly ; the lower ones narrow, slightly covered 

 with loose cottony wool ; the upper ones broader and nearly glabrous. 

 Flower-heads hemispherical, about an inch in diameter, usually 3 or 4 

 in a small terminal corymb. Outer in volucral bracts broadly lanceolate, 

 bordered with very prickly teeth or lobes; inner ones linear, entire, 

 with very smooth and shining, horizontally-spreading tips. 



In dry, hilly pastures, and fields, throughout Europe and Kussian 

 Asia, except the extreme north. Kather common in England and 

 Ireland, extending into a few Scottish counties. PL summer and 

 autumn. 



XXVIII. CENTAUREA. CENTAUREA. 



Herbs, with entire or pinnatifid leaves, seldom prickly, and purple, 

 blue, or sometimes yellow flowers. Involucres globular or ovoid, the 

 bracts numerous, ending either in a prickle or in a fringed or toothed 

 appendage. Outer row of florets usually larger than the others, and 

 neuter. Receptacle bearing bristles between the florets. Achenes 

 glabrous, with a short pappus of simple hairs or scales, sometimes very 

 short, or rarely quite wanting. 



One of the most numerous genera of Cynaroidece in the Mediterranean 

 and Caucasian regions, with a very few American species. The en- 

 larged outer florets, the most prominent character of the genus, are 

 seldom deficient, and that chiefly in a common variety of nigra. In 

 that case the fringed involucral bracts as readily indicate the genus. 



Involucres not prickly, or with very small prickly points to the 



bracts. 

 In volucral bracts with a broad, black, or brown fringed border 



or appendage. 



Leaves mostly entire or toothed. Appendages almost conceal- 

 ing the bracts themselves 1. C. nigtu. 



Leaves deeply pinnatifid. Involucral bracts showing their 



green centres with a black fringed border . . . . 2. C. Scabiosa. 

 Involucral bracts ending in, or bordered by, minute teeth or 



prickles. 



Outer florets bright blue. An erect cornfield annual . . 8. C. Cyanus. 

 Florets purple. A spreading Jersey perennial . . . . 4. c. aspcra. 

 Involucral bracts ending in a long, stout prickle. 



Florets purple 5. C. Calcitrapa. 



Florets yellow 6. C. tohtitialis. 



C. montana, from central and southern Europe, and a few others, are 

 occasionally cultivated in our gardens, and two species from the 

 Mediterranean, C. salmantica and C. paniculata, have been found in the 

 Channel Islands, but do not appear to be established there. 



1. C. nigra, Linn. (fig. 572). Knapweed or Hardheads. A perennial, 

 with erect stems, hard and branched, 1 to 2 feet high. Leaves from 

 linear to lanceolate or oblong ; the upper ones entire or nearly so, 

 clasping the stem at their base ; the lower with a few coarse teeth or 

 ihort lobes ; all green, and rather rough with a few minute hairs^ or 



