Herbs robust, 8–18 dm, densely tomentose. Stems thick, erect, clustered, many-branched, from woody rootstock; branches ascending at 30–50º, strongly zigzag. Leaves: stipules persis­tent, widely ovate to nearly lanceolate, 1.5–5.5 × 0.7–3 cm, base oblique to cuneate, apex acuminate; petiole 2.2–3.5 cm; leaflet blades elliptic to widely elliptic or ovate, 6.5–11 × 2.5–6.5 cm, lateral veins 9–12 pairs, not conspicuously net-veined abaxially, apex acute to acuminate, short-mucronate, surfaces tomentose. Peduncles 7–10 cm; bracts persistent, ovate, 8–14 × 3–8 mm. Racemes 20–40-flowered, 20–45 cm; flowers in whorls of 2–5 or scattered. Pedicels 4–8 mm, densely tomentose. Flowers 1.6–1.8 cm; calyx 7–9 × 5–8 mm at limb, lobes 2–4 mm, equal to or shorter than tube; wing and keel petals asymmetrically oblong-rhombic; ovary densely tomentose; ovules 10–13. Legumes divergent, arcuate, 4.5–6.5 × 0.4–0.5 cm, densely tomentose. Seeds 5–10, brown, reniform, 3.5–4 × 2 mm, not beaked.

Phenology: Flowering May–Jun.
Habitat: Ridgetops.
Elevation: 150–1500 m.

Distribution

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Calif.

Discussion

Thermopsis robusta is a localized, robust taxon known only from Humboldt and Siskiyou counties.

Selected References

None.

Lower Taxa

None.