444 Ordee 10.— COMPOSIT^E. 



4 A. bi(3ent3.ta Mx. Very hirstUe ; st. branohing ; branches simple ; lis. crowded, 

 mostly alternate, closely sessile or partly clasping, undivided, ohhng, with a single 

 tooth or short lobe on each side near the base ; sterile hds. densely spicate, fer- 

 tile axillary ; fr. i-angled, acutely pointed, the 4 ribs produced in 4 short spines. 

 — Op Prairies, 111. to La. Stem 1 — 3f high, with numerous leaves and very dense, 

 terminal spikes. Jl. — Sept. 



46. XAN'THIUffl, Tourn. Clot-weed. Heads heterocephalous. 



Sterile, in globous heads ; scales distinct, in one row ; anthers approxi- 

 mate, but distinct ; receptacle chaffy. Fertile ; involucre 2-leaved, 

 clothed with hooked prickles, 1 or 2-beaked, enclosing 2 flowers ; 

 stamens 0. — ® Coarse weeds with alternate Ivs. 



1 X. Strumarium L. Rough, unarmed, branohing; Ivs. cordate, lobed, .S-veined, 

 unequally serrate ; fr. elliptical, armed with uncinate, stiff thorns, and ending 

 with 2, spreading, straight horns. — A coarse, rough plant, in old fields, &c., N. 

 Eng. and Mid. States. Stem branched, bristly, spotted, 2 — 3f high. Leaves 

 large, on long stalks, rigid. $ Fls. few together, terminal, globular, green ; S 

 in sessile, axillary tufts. Fruit a hard, 2-celled burr, near an inch long, covered 

 with stiff, hooked prickles, which, like those of tho common burdock, serve to 

 disperse the seeds. Aug. — Tariablo; fruit more than 1', or loss than 1' in length ; 

 thorns very close or somewhat scattered ; horns spreading or incurved. (X. 

 echinatura Murray.) 



2 X. apindsum L. Whitish-dovmy, armed with triple, slender, stihaxiUary spinoi, 

 spines at base of tho leaves triple, slender ; Ivs. ovate-lanceolate, cuneate at base, 

 petiolate, 3-lobcd or dentate or entire, under surface and veins above whitish, 

 twice longer than tho spines ; invoL oblong, with slender, uncinate thorns. — 

 Soadsides and fields, Mass. to Penn. and G-a. Plant about If high, very con- 

 spicuously armed with straw-colored spines ^ — 1' long. Heads sessile, sterile in 

 the upper, fertile in the lower axils. Sept. — Nov. 



47. MELAWTHERA, Cass. (Gr. ^eXag, black, Lat. anthera, an- 

 ther.) Heads discoid ; flowers all tubular, i^ ; scales in 2 subequal 

 series ; receptacle chaffy, the pales partly investing the flowers ; 

 achenia short, truncate, angular ; pappus a few minute caducous awris 

 or bristles. — 2| Herbs rough, with square stems, opposite, petioled, 3- 

 veined Ivs. and long peduncled hds. Cor. white. Anth. black, tip- 

 ped with a white appendage. 



M. hastata Mx. Lvs. hastately 3-lobed, acuminate, dentate, on slender petioles ; 

 scales ovate-lanceolate, acuminate, pales rigid, cusp-pointed. — Dry soils, S. Car 

 lo Fla and La. Sts. 3 to 6f high, beautifully variegated with purple, the branches 

 slender, erect, few-flowered. Lvs. deep green, very rough, 4 to 6' long, the 

 upper smaller. Hds. near 6" broad, of stiff scales and singularly contrasted, 

 colors. — Jl. — Sept. 



48. ZIN'NIA, L. (To John Godfrey Zinn, a German botanist, 

 1557.) Heads radiate ; rays $, disk tubular, i^ ; scales of the involucre 

 oval, margined, imbricate ; receptacle chaffy, conical ; pappus of the 

 disk of 1 or 2 erect, flat awns. — (D American herbs, with apposite, 

 entire lvs. and solitary terminal hds. Rays bright colored, showy. 



Z. multiflora L. Lvs. ovate-lanceolate, abrupt at base, scarcely petioled; hds. 

 on peduncles as long as the lvs. ; pales obtuse, entire ; ach. of the disk with one 

 awn. — Fields and waysides, Ga., Fla., to Tex. Sts. 6' to 2f high, simple or 

 nearly so. Lvs. 1 to 2' long, rather obtuse. Ped. enlarged upwards, hollow 

 Bays about 12, oval, scarlet within, yellowish without. May, Jn. § 



2 Z. 61egana L. Lvs. ovate, cordate, sessile-amplexicaul ; hds. on ped. 

 longer than the lvs.; pales serrated; ach. of the disk with 2 awns. — Gardens; 

 Plant tall, elegant and showy, with brilliant fls. of varying colors, as orange, 

 scarlet, crimson, purple, violet and white. Jl, Aug. j- Mexico. 



