Kansas Wildflowers and Grasses

PRAIRIE TREFOIL

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Lotus unifoliolatus (Hook. ) Benth. var. unifoliolatus

[=Lotus purshianus (Benth. ) F.E. Clements & E.G. Clements]

Stafford County, Kansas

Annual

Height: 8-32 inches

Family: Fabaceae - Bean Family

Flowering Period: June, July, August

Also Called:

American bird's-foot trefoil, pursh's deer-vetch.

Stems:

Erect, much branched, silky pubescent when young, glabrous when older.

Leaves:

Alternate, nearly sessile, 3-foliolate; leaflets lanceolate or ovate-lanceolate, 2/5 to 1 inch long, silky-pubescent; tips pointed.

Inflorescences:

1-2 flowers on stalks in upper leaf axils; subtended by single leaf-like bract.

Flowers:

Calyx tubular-bell-shaped, soft hairy; teeth narrowly lanceolate, unequal; corolla papilionaceous, 1/5 to 1/3 inch long, pink with darker veins, white with pink veins, or rarely cream-colored; banner egg-shaped, 1/4 to 1/3 inch long; wings and keel less than 1/4 inch long; keel tip yellowish; stamens 10, 9 united, 1 free.

Fruits:

Pod, spreading or bent downward, straight, narrowly oblong, .8 to 1.6 inches long, circular in cross-section, glabrous; seeds many, tiny, olive to light brown, often mottled, somewhat shiny.

Habitat:

Prairie plains, rocky hillsides, stream valleys, roadsides, dunes waste areas; open, sandy soils.

Distribution:

Central 1/3 and southeast corner.

Forage Value:

Livestock will eat the immature plant.

Uses:

Quail consume the seeds.

Prairie trefoil