272 COMPOSITE. (composite family.) 



Achenia slender or spindle-shaped. Pappus a single row of rather rigid and 

 strongly roughened-denticulate bristles. — Perennial herbs, chiefly of mountains 

 and cold northern regions, with simple stems, bearing single or corymbed large 

 heads and opposite leaves. Flowers yellow. (Name thought to be a corruption 

 of Ptarmica.) 



1. A. mollis, Hook. Soft-hairy; stem leaf// (1° -2° high), bearing 1 to 5 

 heads ; leaves thin, veiny, smoothish when old, toothed ; the upper ovate-lanceolate, 

 closely sessile ; the lower narrower, tapering into a margined petiole ; scales of 

 the involucre pointed ; pappus almost plumose. — Alpine rivulets, mountains of 

 New Hampshire and N. New York, shores of Lake Superior, and northwest- 

 ward. July. 



2. A. nudicaulis, Ell. Hairy and rather glandular (1° -3° high); leaves 

 thickish, 3 - 5-nerved, ovate or oblong, all sessile, mostly entire and near the root, 

 those of the naked stem small and only one or two pairs ; heads several, corymbed, 

 showy. — Damp pine barrens, S. Penn. and southward. April, May. 



6 5. CENTAUREA, L. Star-Thistle. 



Heads many-flowered ; the flowers all tubular, the marginal often much larger 

 and as it were radiate, sterile. Receptacle bristly. Involucre imbricated, the 

 scales margined or appendaged. Achenia compressed. Pappus wanting, or of 

 a few bristles. — Herbs with alternate leaves and single heads. (Named from 

 the Centaur, Chiron.) 



1. C. CVands, L. (Bluebottle.) Scales of the globular involucre fringe- 

 margined ; false rays large; pappus very short; leaves linear, entire, or toothed at 

 the base ; root annual. — Roadsides, escaped from gardens. July. — Flowers 

 blue, varying to purplish or white. (Adv. from Eu.) 



2. C. nIgra, L. (Knapweed.) Scales of the globular involucre appen- 

 daged, and with a stiff black fringe ; rays wanting ; pappus very short ; leaves 

 lanceolate, or the lower lyrate-angled, rough ; root perennial. — Waste places, E. 

 New England. Aug. — Flowers purple. (Adv. from Eu.) 



3. C. CALCfTRAPA, L. ( Star Thistle.) Stem diffusely much branched ; 

 leaves pinnately lobed or spinulose-toothed ; heads sessile, the middle scales of the. 

 ovoid involucre spiny; pappus none; flowers purple; root annual. — Norfolk, 

 Virginia, and Philadelphia. (Adv. from Eu.) 



66. C NIC US, Vaill. Blessed Thistle. 



Heads many-flowered ; the ray-flowers tubular and sterile, shorter than the 

 rest, which are all tubular and perfect. Scales of the ovoid involucre coriaceous, 

 apprcssed, extended into a long and rigid pinnately spinose appendage. Re- 

 ceptacle clothed with capillary bristles. Achenia terete, short, strongly striate, 

 crowned with 10 short and horny teeth, and bearing a pappus of 10 elongated 

 rigid bristles, and 10 short bristles alternate with the last in an inner row. — An 

 annual smoothish herb, with clasping scarcely pinnatifid-cut leaves and large 

 bracted heads. Flowers yellow. (Name from kvi£o>, to prick.) 



1. C. benedictus, L. — Roadsides, southward : rare, scarcely naturalized. 

 (Adv. fromEu.) 



