Herbs perennial, 35–50 cm, antrorse-strigose. Stems erect, branched. Leaves palmate; stip­ules lanceolate, 3–4 cm, margins entire, apex acuminate; petiole 5–20 cm; petiolules to 1 mm; leaflets 5–7, blades linear, linear-elliptic, linear-lanceolate, often folded, falcate, 2–7 × 0.2–0.6 cm, base cuneate, veins thickened, margins setose, apex acute-setiform, surfaces pubescent. Peduncles 10–15 cm. Inflorescences terminal, 60-flowered, in 10–12 whorls, globose or ovoid to subglobose, 3–5 × 3–4 cm; involucres absent. Pedicels reflexed in fruit, 1–1.5 mm; bracteoles minute. Flowers 20–23 mm; calyx campanulate, 6–8 mm, slightly pilose, veins 10–15, tube 2.5–3 mm, lobes equal, subulate, slightly pilose, orifice open; corolla rose-pink to purple, 18–22 mm, banner oblong, folded, 18–22 × 11–13 mm, apex rounded. Legumes flattened, lanceoloid-oblong, 6 mm. Seeds 1 or 2, yellow, often mottled, mitten-shaped, 2.8–3 mm, smooth, glossy. 2n = 16.

Phenology: Flowering May–Jun.
Habitat: Dry talus fans at base of slopes.
Elevation: 100–300 m.

Distribution

• Generated Map
• Legacy Map

Loading map...

Wash.

Discussion

Trifolium thompsonii is known from Chelan and Douglas counties (J. E. Canfield 1977). It is in the Center for Plant Conservation’s National Collection of Endangered Plants.

Selected References

None.

Lower Taxa

None.