272 COMPOSITE. (composite family.) 



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

 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 Ptdrmica.) 



1. A. mollis, Hook. Soft-hairy; stem leafy (l°-2° high), bearing. \ 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. nudieaulis, Ell. Hairy and rather glandular (l°-3° high) ; leaves 

 thickish, 3 - b-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. 



65. 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. Cyantts, 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 icairf'wg ; 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. calct'trapa, L. (Star Thistle.) Stem diffusely much branched ; 

 leaves pinnafefy lobeel 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. CNICUS, 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, 

 appressed, 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 homy 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 pinna tifid-cut leaves and large 

 bracted heads. Flowers yellow. (Name from Kvlfa, to prick.) 



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

 (Adv. fromEu.) 



and 



