Plants finely gray-tomentose; rhizomatous.
Stems 2–4 dm.
Leaves 5–18 cm; leaflets 15–33, obovate to oblong, 15–38 × 7–15 mm, tips obtuse, rounded to truncate, surfaces abaxially villous-tomentose, adaxially appressed-pubescent.
Inflorescences 20–50-flowered, 5–14 cm; pedicels 2–4 mm; bracteoles 1–2.
Flowers divergent or declined; calyces tubular-campanulate, 6–11 mm, tubes 5–8 mm, teeth broadly triangular, 2–3 mm; corollas 9–16 mm, creamy or greenish white; stamens distinct.
Fruits indehiscent, torulose, 30–40 × 3–5 mm, light brown, leathery, densely short villous-tomentose; stipes 3–4 mm.
Seeds 1–2, 4–5 mm.
2n=36, 54.
Woodlands, roadsides. Flowering May–Jun. 100–800 m. Sisk. Native. Endemic to Oregon.
Sophora leachiana is found only in the Siskiyou Mountains of southwestern Oregon. It was discovered by and named after Oregon botanist Lilla Leach. Flowering depends on high levels of light, and when the tree canopy is established plants cease flowering but persist vegetatively. Plants do have vigorous asexual reproduction by rhizomes, but even these patches will die out as the forest matures. Even in populations with high light levels, there are low levels of fruit/seed development.