Ambrosia trifida

Linnaeus

Sp. Pl. 2: 987. 1753.

Common names: Giant ragweed grande herbe à poux
Illustrated
Synonyms: Ambrosia aptera de Candolle Ambrosia trifida var. integrifolia (Muhlenberg ex Willdenow) Torrey & A. Gray Ambrosia trifida var. texana Scheele
Treatment appears in FNA Volume 21. Treatment on page 14. Mentioned on page 11, 15.

Annuals, 30–150 (–400+) cm. Stems erect. Leaves mostly opposite; petioles 10–30 (–70+) mm; blades rounded-deltate to ovate or elliptic, 40–150 (–250+) × 30–70 (–200+) mm, usually some blades palmately 3 (–5) -lobed, bases truncate to cuneate (sometimes decurrent onto petioles), margins usually toothed, rarely entire, abaxial and adaxial faces ± scabrellous and glanddotted. Pistillate heads clustered, proximal to staminates; florets 1. Staminate heads: peduncles 1–3+ mm; involucres ± saucer-shaped, 2–4 mm diam., scabrellous (often with 1–3 black nerves); florets 3–25+. Burs: bodies ± pyramidal, 3–5 (–7+) mm, glabrous or glabrate, spines 4–5, ± distal, ± acerose, 0.5–1 mm, tips straight (bases ± decurrent as ribs). 2n = 24, 48.


Phenology: Flowering Jul–Nov.
Habitat: Disturbed sites, waste places, damp soils
Elevation: 0–1600 m

Distribution

V21-13-distribution-map.gif

Alta., B.C., Man., N.B., N.S., Ont., P.E.I., Que., Sask., Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo., Mexico (Chihuahua)

Discussion

The name Ambrosia ×helenae Rouleau applies to hybrids between A. artemisiifolia and A. trifida. Hybrids between A. bidentata and A. trifida have been recorded. Ambrosia trifida may be no longer extant in British Columbia.

Selected References

None.

Lower Taxa

None.

... more about "Ambrosia trifida"
not tailed +, rounded +  and obtuse +
coherent +  and distinct +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
spiciform +, racemiform +, paniculiform +, glomerate +  and corymbiform +
indeterminate +  and determinate +
John L. Strother +
Linnaeus +
truncate +  and cuneate +
compound +  and simple +
15 cm150 mm <br />0.15 m <br /> (25 cm250 mm <br />0.25 m <br />) +
7 cm70 mm <br />0.07 m <br /> (20 cm200 mm <br />0.2 m <br />) +
4 cm40 mm <br />0.04 m <br /> (15 cm150 mm <br />0.15 m <br />) +
3(-5)-lobed;rounded-deltate;ovate or elliptic +
30mm;70mm +
winged;ribbed;winged;ribbed +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
glabrate +  and glabrous +
tuberculate +  and rugose +
pyramidal +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
barbellulate +  and barbellate +
Giant ragweed +  and grande herbe à poux +
purplish +  and whitish +
villous +, strigillose +, hispidulous +, glabrous +  and warty +
tuberculate +
globose +  and obovoid pyramidal pyriform obconic or fusiform +
fertile +  and bisexual +
Alta. +, B.C. +, Man. +, N.B. +, N.S. +, Ont. +, P.E.I. +, Que. +, Sask. +, Ala. +, Alaska +, Ariz. +, Ark. +, Calif. +, Colo. +, Conn. +, Del. +, D.C. +, Fla. +, Ga. +, Idaho +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Mont. +, Nebr. +, N.H. +, N.J. +, N.Mex. +, N.Y. +, N.C. +, N.Dak. +, Ohio +, Okla. +, Oreg. +, Pa. +, R.I. +, S.C. +, S.Dak. +, Tenn. +, Tex. +, Utah +, Vt. +, Va. +, Wash. +, W.Va. +, Wis. +, Wyo. +  and Mexico (Chihuahua) +
0–1600 m +
stipitate-glandular +, glabrate +  and hairy +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Disturbed sites, waste places, damp soils +
staminate +  and pistillate +
in corymbiform , glomerate , paniculiform , racemiform or spiciform , arrays +  and singly +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
membranous +  and scarious +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
scabrellous +
saucer--shaped +
conspicuous +
petiolate +  and sessile +
incurved;erect +
deltate +
connate +  and distinct +
2-carpellate +
stipitate-glandular +, hirtellous +  and villous +
spatulate;linear +
membranous +
persistent +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
3 cm30 mm <br />0.03 m <br /> (7 cm70 mm <br />0.07 m <br />) +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Flowering Jul–Nov. +
5 +  and 16 +
unequal +  and subequal +
bearing subulate enations +, hairy +  and bristly +
convex;flat +
exalbuminous +
Illustrated +
4 (?) +  and 5 (?) +
acerose +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
prostrate +  and decumbent +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Ambrosia aptera +, Ambrosia trifida var. integrifolia +  and Ambrosia trifida var. texana +
Ambrosia trifida +
Ambrosia +
species +
campanulate +  and cylindric +
straight +
toothed +  and entire +
150 cm1,500 mm <br />1.5 m <br /> (400 cm4,000 mm <br />4 m <br />) +
30 cm300 mm <br />0.3 m <br /> (150 cm1,500 mm <br />1.5 m <br />) +