COMPOSITA. (COMPOSITE FAMILY.) 225 
40. MELANTHERA, Rohr. 
Heads many-flowered ; the flowers all tubular and perfect, 5-cleft. Scales of 
the involucre imbricated in 2 rows. Chaff of the convex receptacle rigid, per- 
sistent, partly sheathing the flowers. Achenia 4-angled, short, truncate at the 
apex. Pappus of 2—several rough rigid deciduous awns or bristles. — Rough 
perennial herbs, with branching 3-4-angled stems, opposite undivided or 3- 
lobed serrate petioled leaves, and scattered heads of white flowers, on long 
peduncles. Anthers black. 
1. M. hastata, Michx. Stem commonly spotted; leaves varying from 
lanceolate to ovate, entire, or more or less hastate-3-lobed, serrate ; scales of the 
involucre lanceolate, acute; chaff of the receptacle spine-pointed. — Light rich 
soil, Florida to South Carolina. Aug. and Sept. — Stem 3? - 6° high. 
2. M. deltoidea, Michx. Leaves deltoid-ovate, undivided ; scales of the 
involucre ovate; chaff of the receptacle obtuse, mucronate. — South Florida. - 
Al. ZINNIA, L. 
Heads many-flowered ; the ray-flowers pistillate ; those of the disk perfect, 
tubular, with 5 velvety lobes. Scales of the involucre imbricated, oval or round- 
ish, margined. Chaff of the conical receptacle clasping the disk-flowers. Ray- 
flowers oblong, rigid persistent. Achenia of the disk compressed, with a 1 —2- 
awned pappus; those of the rays 3-angled, destitute of a pappus. — Annual 
herbs, with sessile entire 3-ribbed leaves, and solitary heads, on long inflated 
peduncles. 
1. Z. multiflora, L. Stem erect, hairy, branching; leaves oblong-lanceo- 
late; chaff of the receptacle obtuse ; pappus of the disk-flowers l-awned ; rays 
red or purple. — Waste places, Florida to North Carolina. Introduced. July- 
Sept. — Stem 1°-2° high. Rays sometimes fading into yellow. 
42. HELIOPSIS, Pers. 
Heads many-flowered ; the ray-flowers pistillate; those of the disk tubular, 
Perfect, 5-toothed. Scales of the involucre in 2-3 rows; the exterior longer, 
leafy. Chaff of the conical receptacle lanceolate, partly clasping the smooth 4- 
angled truncated achenia. Pappus none, — Perennial herbs with the habit of 
Helianthus. Rays yellow. beet 
l. H. levis, Pers. Smooth; stem slender, branching; leaves ovate or 
9vate-lanceolate, acute or acuminate, sharply serrate, 3-ribbed at the base, on 
slender petioles; peduncles elongated; scales of the involucre obtuse; rays 
deciduous. — Dry open woods, Florida, and northward. Aug. and Sept.— 
Stem 2° ~ go high. Leaves 2' —-3' long, sometimes scabrous. 
To 48. TETRAGONOTHECA, Dil. E. 
Heads many-flowered ; the ray-flowers (6 — 9) pistillate; those of wo 
