This section is from the book "Class-Book Of Botany USA&Canada", by Alphonso Wood. Also available from Amazon: Class-Book Of Botany.
47. MELAN'THERA, Cass. (Gr.
, black, Lat. anthem, anther.) Heads discoid; flowers all tubular,
; scales in 2 subequal series; receptacle chaffy, the pales partly investing the flowers; uchenia short, truncate, angular ; pappus a few minute caducous awns or bristles. - Ц. Herbs rough, with square stems, opposite, petioled, 3-veined Ivs. and long peduncled hds. Cor. white. Anth. black, tipped with a white appendage.
M. hastat a Mx. Lvs. hastately 3-lobed, acuminate, dentate, on slender petioles; scales ovate-lanceolate, acuminate, pales rigid, cusp-pointed. - Dry soils, S. Car to 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. ZINNIA, L. (To John Godfrey Zinn, a German botanist, 1557.) Heads radiate ; rays♀ , disk tubular,
; scales of the involucre oval, margined, imbricate; receptacle chafty, conical ; pappus of the disk of 1 or 2 erect, flat awns. - (1) American herbs, with apposite, entire lvs. and solitary terminal hds. Rays bright colored, showy.
Z. niultiflora 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 Rays about 12, oval, scarlet within, yellowish without. May, Jn. §
2 Z. elegans 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. † Mexico.
3 Z. pauciflorum, with bright yellow flowers is sometimes cultivated.
49. HELIOP'SIS, Pers. Ox-eye, (Gr.
, the sun,
, appearance ; flowers radiant like the sun.) Hds. radiate ; involucre imbricate, with ovate, subequal scales; rays linear, large, ; disk
; receptacle chaffy, conical, the pales lanceolate; achenia 4 sided; pappus 0.- Ц Lvs. opposite. Hds. large. Fls. yellow. (Helianthus, L.)
H. laevis Pers. St smooth; lvs. ovate-oblong, coarsely serrate, petiolate, 3-veined, smooth beneath, upper ones usually lanceolate, lower ones more or less truncate at base. - A large, symmetrical plant, in hedges and thickets, U. S. St. angular, striate, di- or trichotomously branched above, 3 to 5f high. Lvs. 2 to 6' by 1 to 4', acute, distinctly 3-veined. branches thickened at the summit, each terminating with a large, solitary, yellow head. Rays lanceolate, broad at base and obtuse at summit. Jn., Jl.
ft. gracilis. Small and slender; lvs. scabrous, ovate-lanceolate, acute at base. - 2f high. (H. gracilis, Nutt.) y. scabra. St. and lvs. scabrous and yellowish-green; lvs. somewhat deltoid, distinctly truncate at base. - Of high. Common in Ind. (II. scabra, Hook.)
50. TETRAGONOTHE'CA, Dill. (Gr.
,four;
, angle;
envelope.) Heads radiate ; involucre double, the outer of 4 leafy bracts united at base, the inner of 8 small scales similar to the chaff of the conical receptacle; achenia smooth, truncate, destitute of pappus. - Ц. Herb clothed with viscid hairs, opposite lvs., with yellow-flowered, large hds.
T. helianthoides L. Sandy soils, Va. to Fla. and Ala. A stout, coarse, unsightly herb, 2f high. Lvs. ovate, sessile, repand-toothed, 3 to 5' long. Hds. 1 or few, on long peduncles, the rays spreading nearly 3'. Cor. strongly veined. Apr - Jn.
51. ECHINA'CEA, Moench. Purple Cone-flower. (Gr.
, the hedgehog; from the character of the pales.) Heads radiate; involucre, scales in 2 rows; ray flowers neutral; disk flowers
; receptacle conic, with rigid, mucronate pales; achenia 4-angled; pappus 0. - Ц Lvs. alternate. Rays purple, pendulous. (Rudbeckia, L., Nutt.)
1 E. purpurea Moench. Very rough; lower lvs. broad-ovate, 5-veined, attentate at base, remotely toothed; cauline lanceolate-ovate, acuminate, nearly entire; rays 12 to 15, very long, defloxed, bind. - Thickets and barrens, W. and S. States. Plant showy, 4f high, branched. Lvs. 4 to 8' long, rough with short, stiff bristles, 3-veined. Hds. large, solitary, on long ped. Disk thickly beset with the stiff, pointed, brown chaff. Rays 2 to 3' long, pendulous, rarely varying to white, †Jl. - Sept.
2 E. angustifolia DC. St. hispid, subsimple, slender, naked above; lvs. entire, hispidly pubescent, 3-veined, lower lanceolate, petiolate, upper lance-linear, sessile; scales in about 2 rows, short; rays 12 to 15, slender, drooping. - Prairies and marshes, I11., Mo. to Tex. Plant of a more slender habit than the last, 2 to 3f high. Hds. on long, naked ped. Rays 1 to 2' long, purple, varving to white. Disk brown. May - Jl.
52. RUDBECKI'A, L. (To the celebrated Olaus Rudbeck, Professor of Botany, at Upsal, Sweden.) Heads radiate ; involucre scales nearly equal, leafy, in a double row, 6 in each ; ray-flowers neutral; disk perfect ; receptacle conic or columnar, with unarmed pales or chaff; achenia 4-angled ; pappus none, or a lacerate or toothed margin. - † Lvs. alternate. Hds. large. Rays yellow.
 
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