394 ORDER LXVIII. COMPOSITE. 



base, 3-lobed. Achenia elliptic, winged; pappus 2 short awns; disk 

 dark purple. — Yellow. June — Sept. Pine-barrens. N. O, Florida, and 

 Texas. 1—3 feet. 



13. C. tenuifo'lia, (Ehr.) (C. verticillata, L.) Stem glabrous, slightly 

 angled, branching toward the summit. Leaves trifoliate, sessile ; leaf- 

 lets many-parted, with linear, entire segments. Flowers in corymbs; 

 exterior involucre with about 8 lanceolate leaves. — Yellow. 2f . July 

 — Aug. Upper Car. 2 — 3 feet. 



14. C. trichosper'ma, (Mich.) Stem glabrous, branching, angular. 

 Leaves opposite, pinnate ; leaflets serrate. Flowers in corymbs ; exte- 

 rior involucre with 8 ciliate leaves ; ray florets 8, entire ; chaff linear -lan- 

 ceolate. — Yellow. 2f. Aug. — Oct. Swamps. Upper Car. 2 — 3 feet. 



Tickseed. Sunflower. 



15. C. mi'tis, (Mich.) (C. Aurea, Ait.) Stem obtusely angled, glabrous, 

 much branched. Leaves decussate, bipinnatifid ; segments linear-serru- 

 late, slightly scabrous. Flowers in terminal panicles ; exterior involu- 

 cre with serrulate, linear leaves ; interior pubescent at the base; ray 

 florets 8, obovate. — Yellow. If. Aug.— Sept. Wet grounds. 3 — 4 

 feet. 



16. C. arista'ta, (Mich.) Stem pubescent. Leaves quinnate ; leaflets 

 pinnate, senate. Flowers large ; florets of the ray entire, broad, ovaL 

 Seed cuneate, obovate, 2-awned ; awns very long, divaricate. — Yellow 

 If. Aug. — Sept. 



17. C. pubes'cens, (Ell.) Stem pubescent, obtusely angled, sparingly 

 branched. Leaves quinnate, pinnate ; leaflets lanceolate, obtuse, entire 

 the lateral ones small. Flowers terminal, on long branches ; exterior 

 involucre about equal to the interior; ray florets 8, broader at the sum- 

 mit. Seed slightly winged. — Yellow. If. Aug. — Sept. Western Geo. 

 2—3 feet. 



18. C. trip'teris, (L.) Stem glabrous, branching toward the summit, 

 fistular. Leaves opposite, the upper ones trifoliate ; leaflets lanceolate, 

 glabrous, entire, scabrous along the margin ; radical leaves pinnate ; ex- 

 terior involucre not as long as the interior ; ray florets entire, 8. Seed 

 slightly winged. — Yellow. 2f. Aug. — Oct. Western Geo. 4 — 6 ft. 



19. C. nuda'ta, (Nutt.) Stem erect, glabrous, striate, dichotomously 

 divided toward the summit. Leaves subulate, linear, glabrous, those 

 near the summit smaller. Flowers terminal ; exterior involucre minute. 

 — Red. If. July — Aug. Southern Geo. 2 — 3 feet. 



c. Leaves alternate. 



20. C. gladia'ta, (Walt.) Stem glabrous, striate, dichotomously di- 

 vided toward the summit. Leaves narrow, lanceolate, entire, succu- 

 lent ; radical ones on long petioles. Flowers terminal ; exterior invo- 

 lucre smaller than the interior, expanding ; ray florets 3 lobed at the 

 summit, 8. Seed with serrulate wings ; pappus pilose ; chaff purple.— 

 Yellow. If. Aug. — Sept. Damp pine-barrens. 2 — 3 feet 



