Trifolium aureum

Herbs annual, 20–60 cm, glabrous or hirsute. Stems erect, unbranched or profusely branched. Leaves palmate; stip­ules oblanceolate, 0.9–1.5 cm, margins entire, apex acuminate or cuspidate; petiole 0.8–1 cm; petiolules 0–1 mm; leaflets 3, blades obovate to elliptic-lanceolate, 1–2.8 × 0.6–0.8 cm, base cuneate, lateral veins prominent, ± parallel, ascending, margins denticulate, apex acute, truncate, or retuse, mucronate, surfaces glabrous or sparsely hairy. Peduncles 2–5 cm. Inflorescences axillary or ter­minal, 20–80-flowered, usually ovoid-cylindric, some­times globose, 1.2–2 × 1.3 cm; involucres absent. Pedicels reflexed, 0.3–0.6 mm; bracteoles a fringe of red setae. Flowers 7–8 mm; calyx campanulate, 2–2.5 mm, glabrous, veins 5, tube 0.8–1 mm, lobes unequal, adax­ial deltate, 0.6–0.9 mm, 1/2 length of abaxial, abaxial linear, orifice open; corolla golden yellow becoming brown, 5–6 mm, banner persistent, obovate, boat-shaped, 4–4.5 × 2.4–2.6 mm, apex emarginate. Legumes stipitate, oblong, 3–3.5 mm, longer than calyx. Seeds 1, pale yellow-green, ovoid, 1–1.2 mm, smooth, glossy. 2n = 14, 16.

Phenology: Flowering Jun–Aug.
Habitat: Roadsides, railroads, fields, disturbed woodland glades.
Elevation: 0–1700 m.

Distribution

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Introduced; St. Pierre and Miquelon, Alta., B.C., Man., N.B., Nfld. and Labr., N.S., Ont., P.E.I., Que., Sask., Alaska, Calif., Conn., Del., D.C., Ga., Idaho, Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., Mont., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., S.C., Tenn., Vt., Va., Wash., W.Va., Wis., Wyo., n, c Europe, w Asia, introduced also in s South America (Argentina, Chile), e Asia (e China), Pacific Islands (New Zealand), Australia.

Discussion

Trifolium agrarium Linnaeus is a rejected name that has been used historically for T. aureum (J. E. Dandy 1958; N. J. Turland et al. 1996).

Selected References

None.

Lower Taxa

None.