CaLENDULA. LXXV. COMPOSITZ. 353 
59. AMBROSIA. | 
Gr. apBpocra, food of the gods ; a term strangely applied. 
Heads heterocephalous. Sterile—Involucre of several united 
scales, hemispherical, many-flowered ; anthers approximate, but dis- 
tinct ; receptacle naked. vrtile—Involucre 1-leaved, entire or 5- 
toothed, 1-flowered, corolla 0; styles 2; stamens 0.—Herbaceous 
plants with mostly opposite lvs. and unsightly flowers. 
1. A. TRIFipA. Tall Ambrosia. : 
Hairy, rough; dvs. three-lobed, serrate, the lobes oval-lanceolote, acumi- 
nate ; fr. with 6 lines below the summit.—@ A very tall, herbaceous plant, not 
very common in N. Eng., found in hedges and low grounds in the valley of 
Connecticut river.. In the W. States it is abundant! Stem 5—10f high, erect, 
branching, furrowed. Leaves opposite, in 3 large, deep lobes with long points 
and close serratures. Flowers mean and obscure, in long, leafless spikes, axil- 
lary and terminal. Aug. 
8. integrifolia. T. & G, (A. integrifolia. Mudl.) Lws. ovate, acuminate, 
serrate, bristly on both sides, ciliate at base, often some of them 3-lobed; rac. 
terminal, single or ternate. 
2. A. ARTEMISIEFOLIA. (A. elatior. Ph.) Hog-weed. 
Iws. twice-pinnatifid, nearly smooth; petioles ciliate; rac. terminal, pani- 
cled; st. virgate—@ A commonand troublesome weed of the gardens, fields, 
&ec. Sire to Ga.) far more worthy of its English than its Latin name. Stem 
2—3f high, branching, pubescent when young. Leaves with segments acute 
and parallel. Barren flowers, small, green, in terminal racemes, the fertile 
ones sessile about the axils of the upperleaves. Aug. Sept. 
3. coronoPiFouia. Torr. & Gray. 
Canescent-strigose, branched; lvs. crowded, rigid, the lower opposite, bi- 
pinnatifid, upper lanceolate, sessile, pinnatifid ; sterile hds. spicate, fertile clus- 
tered at the base of the sterile spikes, in the axils of the upper leaves; fr. hairy. 
—(@ Prairies, Wis. to Tex. Stem 1—5f high, at length very branching and 
leafy. Aug. Sept. 
4. A. piwenTata. Michx. 
Very hirsute; st. branching; branches simple; lvs. crowded, mostly alter- 
nate, closely sessile or partly clasping, undivided, oblong, with a single tooth 
or short lobe on each side near the base; sterile hds. densely spicate, fertile axil- 
lary; fr. 4-angled, acutely pointed, the 4 ribs produced in 4 short spines. @ 
Prairies, Ill. to La. Stem 1—3f high, with numerous leaves and very dense, 
terminal spikes. J]_—Sept. 
60. IVA. 
A name of barbarous origin. 
Heads discoid ; involucre 3-leaved; marginal flowers 5, fertile, the 
others sterile; receptacle hairy; achenia obconic, obtuse; pappus 0. 
—AHerbs or shrubs. Lower lvs. opposite. 
I. rrRuTEScENS. High-water Shrub. Marsh Elder. 
St. shrubby; /vs. lanceolate, punctate, deeply serrate, rough.—| In the 
borders of salt marshes, Mass. to La., common. Stem thick, 3—8f high, with 
numerous opposite branches. Leaves numerous, 3-veined, upper ones entire. 
Flowers green, small, drooping, in close, leafy clusters. Aug. 
Treed5. CYNAREX. 
Heads ovoid, discoia, rarely radiate, homogamous (rareiy aicecious), or hete- 
rogamous with the marginal flowers in a single series. Style in the perfect 
flowers often tumid near the summit. 
61. CALENDULA. 
Lat. calenda, the first day of the month ; some species blossom monthly. 
Heads radiate ; involucre of many equal leaves, in about 2 series ; 
