272 COMPOSITE. (COMPOSITE FAMILY.) 



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

 strongly roughened-dcnticulate 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 Ptarnrica.) 



1. A. mollis, Hook. Soft-hairy; stem leafy (l-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. nudicatllis, Ell. Hairy and rather glandular (1 -3 high) ; leaves 

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

 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. CENTAUBEA, 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. CYANUS, 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. 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 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 KI/I'^W, to prick.) 



1. C. BENEDICTS, L. Roadsides, southward : rare, scarcely naturalized. 

 (Adv. fromEu.) 



