Herbs perennial, 20–75 cm, gla­brous or slightly pilose. Stems erect, unbranched or sparsely branched. Leaves palmate; stip­ules lanceolate to ovate, 1.5–6.5 cm, margins setose-serrulate or entire, apex acuminate; petiole 1.5–15 cm; petiolules 1 mm; leaflets 3, blades elliptic-oblanceolate to linear-elliptic, 3–9.5 × 0.5–1.6 cm, base cuneate, lateral veins prominent, recurved, dichotomously forked near margin, margins setose-denticulate to serrate, apex rounded or acute, surfaces glaucous, glabrous, sometimes sparsely pubescent abax­ially. Peduncles 3–12 cm. Inflorescences terminal or axillary, 30–50+-flowered, umbellate, globose to ovoid, 1.5–5 × 2–3.5 cm; involucres absent. Pedicels erect or slightly reflexed, to 0.2 mm; bracteoles minute. Flowers 14–16 mm; calyx campanulate, 6–9 mm, pilose, veins 15–20, tube 1.5–3 mm, lobes unequal, narrow, triangu­lar or subulate, abaxial lobe straight, lateral and adaxial tortuous, recurved inwards around corolla, orifice open; corolla magenta, 12–16 mm, banner oblong, 12–16 × 4–6 mm, apex flared, acute or obtuse; ovaries glabrous or pubescent distally. Legumes ovoid, 3–4.5 mm. Seeds 1 or 2, tan to brown, ovoid, 1–1.5 mm, slightly roughened. 2n = 16.

Phenology: Flowering Jun–Jul.
Habitat: Moist meadows, rich soils in prairies, stream bottoms and banks, openings in pine forests.
Elevation: 600–1500 m.

Distribution

• Generated Map
• Legacy Map

Idaho, Oreg., Wash.

Discussion

Trifolium douglasii is rare throughout its range and has been impacted by agricultural practices (P. Camp et al. 2011).

Selected References

None.

Lower Taxa

None.