190 COMPOSITE. 



late, squarrose, hispidly ciliate. H. frondosm Hook. H. strumosus and 

 tenuifolius Ell. 



Rocky woods. Can. to Geor. Aug. Oct. f Z}_. Stem 3 5 feet high, slender, 

 somewhat branching at the summit. Heads in a fastigiate corymb ; rays 8 10 ; 

 narrow, pale-yellow. Thin-leaved Sunflower. 



7. H. trackelifolius Willd. : stem rough, branched above ; leaves ovate- 

 lanceolate, acuminate; serrate, 3-nerved, very scabrous on both sides, con- 

 tracted into a short petiole, the upper alternate; scales of the involucre 

 linear-lanceolate, ciliate, outer ones large and squarrose. 



Woods. Can. to Car. Aug. Oct. QJ.. Stem 34 feet high. Heads in a 

 loype terminal panicle ; rays 10. Wild Sunfloiver. 



8. H. gig anteus Linn. : stem tall, scabrous; leaves lanceolate, acuminate, 

 somewhat serrate, obscurely 3-nerved, very rough, attenuate and ciliate at 

 base, the upper alternate ; scales of the involucre linear-lanceolate, acu- 

 minate, ciliate. H. altissimus Willd. 



Dry swamps. Can. to Car. Aug., Sept. 'Zj.. Stem 5 8 feet high, panicu- 

 lately branched at the summit, sometimes smoothish below. Heads in a loose 

 terminal panicle ; rays 12 20, sulphur yellow ; disk greenish yellow. 



Tail Sunflower. 



9. H. microcephalus Torr. <$ Gr. : stem smooth, 2 3-chotomously 

 branched; leaver mostly opposite, membranaceous, ovate-lanceolate, acu- 

 minate, somewhat serrate, petioled, 3-nerved, scabrous above, tomentose- 

 pubescent beneath ; scales of the involucre ovate-lanceolate, ciliate, the 

 outer with squarrose tips. H. divaricatus Mich. 



Woods. Can. Penn. to Geor. W. to Ken. July Sept. 7J. Stems usually 

 in tufts, 3 6 feet high. Heads small, oblong ; rays 5 6, about an inch long. 



Small-headed Sunflower. 



ff Leaves alternate, sometimes opposite below. 



10. H. multiflorus Linn. : stem erect, branching, scabrous ; leaves alter- 

 nate, petioled, toothed, 3-nerved, scabrous, serrate ; lower cordate, upper ovate ; 

 outer scales of the involucre linear-lanceolate, ciliate, inner lanceolate. 



Mountain woods. Arct. Amer to Can. Penn. to Car. Hook. $ Pursh. July 

 Sept. 1|-. Stem and peduncles scabrous. Leaves sometimes opposite. Involucre 

 with 4Q 50 scales, imbricate, not squarrose. Heads erect ; rays numerous, 

 oblong. Perhaps not a native. Many-rayed Sunflower. 



11. H. tuberosus Linn. : root creeping, bearing an oblong tubercle ; stem 

 erect, branching, rough ; leaves alternate, petiolate 3-nerved, scabrous, 

 serrate; lower cordate-ovate, upper ovate-acuminate; petioles ciliate at 

 base ; scales of the involucre linear-lanceolate, ciliate. 



Fields and cultivated grounds. N. S. July Sept. 7].. Stem 48 feet high. 

 Leaves large, cuneate at base; the lower ones opposite, rarely ternate. Heads 

 rather large, terminal, on angular pubescent peduncles; rays numerous, yellow. 

 Naturalized in various parts of the U. S. Jerusalem Artichoke. 



36. BIDENS. Linn. Bur-Marigold. 



(From the Latin bidens, having two teeth ; in allusion to the awns of the 

 achenia.) 



Heads many-flowered ; the ray-flowers neutral, often want- 

 ing ; those of the disk tubular, perfect. Involucre double, un- 



