Ambrosia trifida

Linnaeus

Sp. Pl. 2: 987. 1753

Common names: Giant ragweed grande herbe à poux
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.
Click plate for higher resolution version.
Illustrator: Barbara Alongi
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 gland-dotted. 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.

References

None.

Lower Taxa

No lower taxa listed.

Facts about "Ambrosia trifida"
AuthorJohn L. Strother +
AuthorityLinnaeus +
Common nameGiant ragweed + and grande herbe à poux +
DistributionAlta. +, 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). +
Elevation0–1600 m +
HabitatDisturbed sites, waste places, damp soils +
IllustratorBarbara Alongi +
PhenologyFlowering Jul–Nov. +
Publication titleSp. Pl. +
Publication year1753 +
ReferenceNone +
Source xmlhttps://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f6b125a955440c0872999024f038d74684f65921/coarse grained fna xml/V19-20-21/V21 13.xml +
SynonymsAmbrosia aptera +, Ambrosia trifida var. integrifolia + and Ambrosia trifida var. texana +
Taxon familyAsteraceae +
Taxon nameAmbrosia trifida +
Taxon parentAmbrosia +
Taxon rankspecies +
VolumeVolume 21 +